Three-dimensional volumetric analysis of gingival augmentation for the treatment of multiple recession defects by vestibular incision subperiosteal tunnel acces (VISTA)

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Content 1 Three-‐‑dimensional volumetric Analysis of Gingival Augmentation for the treatment of multiple recession defects by Vestibular Incision Subperiosteal Tunnel Access (VISTA) Authors: Alfonso Gil, DDS Division of Periodontology, Diagnostic Sciences & Dental Hygiene University of Southern California Ostrow School of Dentistry 925 34th Street Room 4278 Los Angeles, CA 90089-0641 Correspondence: Gil.alfon@ hotmail.com Conferring Program: Master of Science, CBY Conferring Date: August 2016 2 Index 1-‐‑ TITLE 3 2-‐‑ABSTRACT 4 3-‐‑KEYWORDS 6 4-‐‑INTRODUCTION 7 5-‐HYPOTHESIS 12 6-‐‑OBJECTIVES 13 7-‐‑MATERIAL AND METHODS 14 8-‐‑RESULTS 17 9-‐‑DISCUSSION 24 10-‐‑CONCLUSIONS 31 11-‐‑BIBLIOGRAPHY 32 12-‐‑TABLES/FIGURES 37 3 1-‐‑Title Three-‐‑dimensional volumetric Analysis of Gingival Augmentation for the treatment of multiple recession defects by Vestibular Incision Subperiosteal Tunnel Access (VISTA). 4 2-‐‑Abstract Aim: Treatment of multiple contiguous recession defects, in particular in sites with interproximal periodontal attachment loss remains a clinical challenge. Vestibular Incision Subperiosteal Tunnel Access (VISTA) has been developed as a technique well suited for these clinical scenarios. The present study sought to analyze retrospective data on patients treated with VISTA to achieve periodontal root coverage for the treatment of multiple contiguous recession defects. The aim of this study was to determine the efficacy of VISTA for root coverage and gingival thickness/volume gain, and to determine the role of various risk factors (initial root prominence, initial gingival margin thickness, initial recession depth, recession type, tooth type, graft type and anatomic location) Material and methods: Thirteen patients with 86 teeth exhibiting multiple gingival recession defects (mean initial recession 2.3 mm±0.9) were treated with VISTA using various graft materials. Treated root surfaces were thoroughly debrided with scaling and root planning. Odontoplasty was performed to reduce root prominence, and exposed root surfaces were conditioned with EDTA. VISTA entailed a vertical incision in the vestibule, through which a subperiosteal tunnel was created, extending towards the vestibular depth and gingival margins. The tunnel was coronally advanced and stabilized with sutures that were bonded to the facial surface of the teeth. Graft material included autogenous connective tissue from palate/tuberosity, acellular dermal matrix (ADM; Perioderm), or xenogenic collagen matrix (XCM; Mucograft). Sutures were removed after 3 weeks. Retrospective data on patients treated, including clinical and study models was collected in an effort to examine therapeutic effectiveness of various clinical cases. The outcome of soft tissue augmentation was assessed by 3-‐‑dimensional analysis, comparing pre-‐‑ and post-‐‑therapy study casts. Study casts were made from alginate impressions at baseline and at various intervals after surgery. The pre-‐‑ and post-‐‑op study models were scanned with 3-‐‑D scanner (3 Shape) and saved as STL files. These were imported into the reverse engineering software (Geomagic Control) and superimposed to allow for comparison of volumetric changes. The changes in gingival volume, soft tissue thickness, percentage of root coverage and complete root coverage were calculated. Results: The mean percentage of root coverage achieved was 102.0 ± 10.0% for Miller Class I/II and 83.0 ± 14.0% for Class III recession defects. Complete root coverage was 71.0% for Miller Class I/II recession defects, and 16.0% for Miller Class III. The mean gingival volume gain was 3.8 ± 1.8 mm3 and 5.9 ± 6.9 mm3 for Class I/II and III, respectively. The gingival thickness gain was 1.0 ± 0.3 mm, 1.0 ± 0.4 mm, 0.9 ± 0.4 mm, 0.9 ± 0.4 mm and 0.8 ± 0.4 mm at 1, 2, 3, 4, 5 mm, from the final gingival margin, respectively. Root prominence showed a statistical significant negative correlation with percentage of root coverage (p=0.0001). Pre-‐‑operative gingival margin thickness and incisor teeth showed a statistical significant positive correlation with percentage of root coverage (p=0.0001). The types of graft material used 5 (palatal/tuberosity CTG, ADM, XCM) and the anatomic location of the tooth (maxillary vs mandibular) showed no statistical difference in any of the parameters measured. Conclusions. The present pilot study demonstrated that 3D volumetric measurement can provide a quantitative tool to examine the efficacy of treatment of gingival recession defects. The results of this study suggest root prominence as an important negative predictor of root coverage. Additional predictors of outcome included tooth type (incisor, canine, premolar or molar), interproximal tissue loss (Miller class I/II vs III) and pre-‐‑operative gingival margin thickness. It can be concluded that VISTA shows favorable outcomes in root coverage, volume gain and gingival biotype modification after a mean follow up period of 12 months after surgery. 6 3-‐‑Keywords Mucogingival surgery, gingival recession, periodontal root coverage, periodontal regeneration, connective tissue graft. 7 4-‐‑Introduction Gingival recession is defined as the apical migration of the gingival margin in relationship with the cementoenamel junction in one or multiple teeth. This is one of the most common periodontal findings, affecting more than 80% of the population. (Chambrone et al., 2010) Anatomic factors, trauma from brushing, periodontal disease and tooth malposition are the main risk factors for the development of these periodontal defects. Gingival recession is often associated with aesthetic problems and dentinal hypersensitivity (Chambrone et al., 2010). Irregularities of gingival margin contour may also pose difficulty for patients to perform adequate oral hygiene, leading to accumulation of plaque and gingival inflammation. Sites with gingival recession also have increased susceptibility to future gingival recession (Serino et al., 1994). The negative consequences associated with gingival recession provide a rationale for the treatment of certain gingival recession defects. A wide variety of surgical techniques have been utilized for soft tissue augmentation around teeth. From the 1950s to the 1970s repositioned periodontal flaps began to be used for the treatment of recession type defects. These techniques entailed the displacement of a partial thickness pedicle graft adjacent to the recession in a lateral/oblique manner to cover the denuded root surface. (Grupe and Warren 1956, Corn et al., 1964, Pennel et al., 1965, Cohen et al., 1968) The clinical outcomes of all these techniques improved, but the donor site always healed though secondary intention healing. Later on, repositioned flaps were modified to substitute lateral sliding flaps for coronally advanced flaps (Bernimoulin et al., 1975). This technique utilized periosteal releasing incisions to mobilize the flap in a coronal direction to cover denuded roots. Many clinicians that soon made modifications of the technique adopted the concept. (Tarnow et al., 1986, Romanos et al., 1993) Miller described the use of free epithelialized grafts, containing both the epithelium and connective tissue for gingival augmentation and root coverage. This free graft would be stabilized over the recipient area with sutures after dissection of a partial thickness and apically positioned flap. (Holbrook et al., 1983) This technique was developed for areas lacking keratinized tissue but also for the purpose of root coverage. The main disadvantages are the aesthetic problems due to lack of color match with the recipient area and the patient morbidity because of the secondary intention healing in the palate. (Douglas de Oliveira et al., 2013) In 1985 Langer and Langer (Langer et al., 1985) introduced the sub epithelial connective tissue graft (SCTG) for mucogingival therapy and root coverage. After having raised a split thickness flap, this graft would be stabilized over the denuded root area with sutures and would then be left uncovered over the recession sites. This technique decreased the morbidity of the surgery and improved the clinical results of the procedure. 8 Furthermore, different approaches were described to utilize the connective tissue graft in with more predictable results. (Raetzke et al., 1985, Allen et al., 1994) Finally, after the year 2000, long term outcomes were reported for the use of a coronally advanced flap and a connective tissue graft combined. (Zabalegui et al., 1999, Zucchelli et al., 2000, Carvalho et al., 2006, Zadeh et al., 2011, Zuhr et al., 2014, Bethaz et al., 2014). The connective tissue graft would be placed in the recipient area through a tunnel or through a raised flap and then the tunnel/flap would be repositioned coronally. An increasing number of publications supported these techniques. Not only descriptive papers but also randomized controlled clinical trials strengthened the current periodontal literature supporting this type of surgery. Recent systematic reviews have widely reported the coronally advanced flap (CAF) in combination with a connective tissue graft as the gold standard for soft tissue augmentation and periodontal root coverage. (Buti et al., 2013, Chambrone et al., 2015) Multiple randomized controlled clinical trials have demonstrated successful recession reduction, clinical attachment level gain and increased zone of keratinized tissue. (Aroca et al., 2013, Zucchelli et al., 2009) The techniques mentioned above have shown positive outcomes, especially in cases when there is no loss of the interproximal bone: recession defects class I and II, according to the Miller Classification. (Miller et al., 1985) These type of recession defects present with more remaining blood supply adjacent to the defect site when there is intact interproximal bone and periodontal attachment. Subsequently there is a better chance of obtaining complete root coverage, regardless of the technique used. Conversely, in sites with loss of interdental bone and attachment (Miller class III and IV), root coverage procedures have reduced efficacy and less predictability. (Chambrone et al., 2015, Cortellini & Pini Prato 2012) The limitation of root coverage correlates to the level of interproximal bone that will provide blood supply during healing process. The evidence on the treatment of gingival recession defects type III is scarce and only a few randomized controlled clinical trials have addressed this issue. (Aroca et al., 2010, Cairo et al., 2012, Henriquez et al., 2010) These studies show heterogeneous results with a mean root coverage ranging from 55 to 85%. (Chambrone et al., 2015) More studies are needed to determine the outcome of treatment of these periodontal defects. Gingival recession may also be part of a generalized condition that presents itself with multiple recession type defects and is usually associated with previous history of periodontitis. This is the reason why some root coverage procedures nowadays attempt to cover more than one tooth with recession, therefore reducing the morbidity of multiple surgeries for the patient. 9 Nevertheless, this common clinical situation has not been studied enough in the periodontal literature. In fact, there are not many prospective studies assessing the treatment of multiple recession type defects. Two systematic reviews have revised this. (Chambrone et al., 2009, Hofmänner et al., 2012) Both conclude using the scarce available literature, that in the presence of pristine interdental attachment (gingival recession class I and II) multiple recession type defects can benefit from root coverage procedures when a coronally advanced flap is combined with the use of a connective tissue graft. The results show a mean root coverage ranging from 91 to 98%, which remains stable in a short period of time. Such results suggest that we can improve most clinical parameters by performing periodontal plastic surgery for these type of recessions in cases where there is no interproximal bone loss. For adjacent recession defects that are class III, there is very limited data on clinical trials. (Chambrone et al., 2009) Vestibular Incision Subperiosteal Tunnel Access (VISTA) may be well suited for the treatment of multiple recession type defects with presence of interproximal bone loss. VISTA consists of a vertical incision done in the vestibule, remote from the recession area. Through this incision, a subperiosteal tunnel is created using a series of specially designed elevators, extending towards the vestibular depth as well as the gingival margin and papillae. This type of tunneling produces a tension free method of mobilizing the mucoperiosteal complex in a coronal direction. Sutures are placed in the mucosal margin and fixated to the teeth with bonded resin. Then, an autogenous connective tissue graft or graft substitute is inserted inside the tunnel and the vertical incision is approximated with suture. This technique is based on the concept of a coronally advanced tunnel with an autogenous or synthetic graft, where no incisions are made on the gingival margin, to preserve the blood supply, and there is an important coronal displacement of the whole mucogingival complex with bonded sutures to the buccal surface of the teeth. (Zadeh et al., 2011) This technique can be applied for the treatment of multiple recession type defects. The tunnel will usually include at least one tooth mesial and distal to the area that needs treatment. A wider the tunnel in a mesio-‐‑distal dimension, will provide a greater tension free coronal displacement of the mucogingival complex. Absence of interproximal incisions in conjunction with coronal displacement of uninterrupted blood vessels of the flap can provide additional blood supply for improved healing potential of miller class III recession defects where there is interproximal loss of bone and reduced apical perfusion to the graft. Different predictive factors have been described in the literature for the treatment of gingival recession defects. A study by Cortellini and Pini Prato (Cortellini & Pini Prato 2012) presented different risk factors, categorized into 3 groups: patient factors, tooth factors and defect/site factors. Mainly, the most important risk factors for this type of procedure are smoking, presence of interproximal bone loss (gingival recession type 10 III, IV), thin biotype and deep initial recession (more than 4 mm). All of these are supported by different prospective studies. There are other risk factors that have weaker evidence, such as tooth type, oral hygiene, anatomic location, abrasion in the cervical area and papilla morphology. These have been described in retrospective studies but are lacking stronger evidence. There is a need for understanding the influence of such risk factors in outcome of therapy and whether there are still any other factors yet to be identified. In order to determine the efficacy of various techniques of soft tissue augmentation, it will be necessary to utilize quantitative methods that can precisely measure changes achieved after therapy. Classically the way to interpret the data in clinical studies on the treatment of recession type defects has been with direct intraoral measurements. The most common method used for quantifying the efficacy of various soft tissue augmentation techniques is linear measurement using a periodontal probe. It is apparent that this method will be limited by the errors associated with utilizing an instrument that measures at millimeter level. First, limited visual access to the area that is being analyzed may be present. Second, differences in angulation and projection of the instrument can cause reading errors in the quantification of the measurement. In addition, such measurements are usually rounded to the next millimeter. (Badersten et al., 1984) Periodontal probe is the instrument of choice for measurement changes in different types of soft tissue conditions, such as probing pocket depth, width of keratinized tissue and the amount of gingival recessions depth. Different types of periodontal probes can be found in the market. They show different horizontal markings at defined intervals (usually at each 1, 2, or 3 mm) for visual measurements, and the tendency is to round values to the next millimeter. Because of this tendency to round off numbers, a measurement error of approximately 1 mm can occur. This has been shown in the literature before, where different clinical studies have assessed differences in periodontal pocket depth probing. (Osborn et al., 1990; Wang et al., 1995) While assessing the outcomes of different treatment options, such methodological inaccuracies could affect the specificity of the results, therefore potentially leading to imprecise conclusions of treatment outcomes. Therefore, it is important to find more precise measurement techniques that can ensure a more accurate data collection for analysis. Digital technologies are becoming more established in everyday dentistry and have evolved tremendously to become more efficient and accurate. They can be used in all sorts of different scenarios in dentistry, from computer-‐‑aided design of prosthetic components, to optical surface scanning and volumetric data analysis. Images that are obtained from optical scanning can be analyzed and measured at different magnifications and directions, thus being able to make accurate 11 measurements of even a tenth of a millimeter. Also, optical scanning allows for not only linear measurements but also volumetric analysis in 3 dimensions. This is a unique characteristic for this type of measurement technique, that is unprecedented for any type of clinical measurement. (Schneider et al., 2014) Digital imaging may therefore introduce a clear advantage in measurement method for data collection in periodontal research, potentially improving quality and reliability of data acquisition. This has already been shown in other areas of dentistry where different clinical scenarios have been analyzed through this new technology with promising results. (Fickl et al., 2009, Thoma et al., 2010, Schneider et al., 2011) There is a great potential to utilize digital analysis to find new and solid evidence, especially, in the field of gingival augmentation around teeth. Only a few studies have been published regarding this concept (Rebele et al., 2014, Schneider et al., 2014), where the possibility of examining 3 dimensional soft tissue aspects following root coverage procedures is presented with great success. The present study sought to utilize 3D volumetric method to compare the pre-‐‑ and post-‐‑therapy study models of patients treated with VISTA technique for multiple gingival recession type defects and to examine which predictive factors may play a role in outcome of root coverage. 12 5-‐‑Hypothesis 1-‐‑The treatment of multiple recession defects by Vestibular Incision Subperiosteal Tunnel Access (VISTA) achieves root coverage, gingival thickness and gingival volume gain. 2-‐‑The ability to achieve periodontal root coverage with VISTA, depends on a number risk factors. (initial root prominence, initial gingival margin thickness, initial recession depth, recession type, tooth type, graft type and anatomic location) 13 6-‐‑Objectives The aim of this study was to analyze retrospective clinical data and study casts to determine the efficacy of VISTA for root coverage and gingival thickness/volume gain, and to determine the role of various risk factors on the outcome of VISTA. To that end, the role of anatomic properties of teeth (initial root prominence, initial gingival margin thickness, initial recession depth, recession type, tooth type and anatomic location), and graft material used, were considered on the outcomes achieved. The outcome measurement examined included percentage of sites with complete root coverage, percentage of root coverage, gingival volume and gingival thickness gain. 14 7-‐‑Material and Methods This study was designed as a retrospective analysis of clinical data, as well as study casts of patients treated with VISTA for gingival recession defects. Three-‐‑dimensional volumetric image analysis was used to perform quantitative assessment of therapy-‐‑ associated gingival changes. A-Sample Characteristics The study sample consisted of 13 patients contributing 86 teeth with multiple gingival recession type defects. (mean initial recession of 2.3 mm ± 0.9) The average was 6.6 recession defects per patient, ranging from 2 to 12 recession defects treated per patient. The mean age of the patients was 53 ± 15 years (ranging from 18 to 71). There were 4 males and 9 females in the study. Patients had a minimum follow up period of 6 months and a maximum follow up period of 25 months (mean follow up 12 months). All participants met the study inclusion criteria: • Age > 18 years • Full mouth plaque and bleeding scores of less than 20% • Multiple (≥2) Miller (1985) Class I, II or III recession defects (≥1 mm in depth) on adjacent teeth • Presence of identifiable CEJ Study exclusion criteria: • smoking more than 10 cigarettes a day • Miller Class IV gingival recession • Patients with untreated periodontal disease or with contraindications for periodontal surgery • Patients taking medication that could affect gingival health or anatomy All patients were treated in a private practice setting by the same periodontist and received mucogingival surgery to achieve periodontal root coverage using VISTA Technique. Alginate impressions were taken at pre-‐‑ and post-‐‑therapy measurement periods. 15 B-‐‑Clinical Intervention The use of graft material included autogenous connective tissue from palate or tuberosity, acellular dermal matrix (ADM; Perioderm) allograft or xenogenic collagen matrix (XCM; Mucograft) incubated with platelet derived growth factor (PDGF). All patients were treated by VISTA, the steps of which consisted of (see Figure 1): -‐‑Use of local anesthesia through infiltration or block anesthesia. -‐‑Scaling and root planning to remove all plaque, calculus and stains. -‐‑Odontoplasty to flatten excessive root prominences in cervical areas. -‐‑Application of EDTA gel (24% pH balanced; PrefGel, Straumann) for 3 minutes. -‐‑Vertical incision in vestibular fornix, remotely position from treated teeth. The typical locations included midline frenum for maxillary anterior teeth or between canine and lateral incisors for maxillary posterior and all mandibular teeth. -‐‑A subperiosteal tunnel was created using specially designed elevators (VISTA elevators, DoWell Dental Products, USA) extending from the vestibule to the gingival margin and interproximally to the extent accessible by instruments. -‐‑Placement of single loop monofilament suture (6.0 polypropylene suture with 13mm 3/8 needle) approximately 3 mm apical to the gingival margin with the knots positioned approximately 3mm coronal to the gingival margin. -‐‑Etching of all teeth for 10 secs. If crown restorations present, etching for 1 minute with porcelain etchant. -‐‑Coronally repositioning of each gingival margin at least 2 mm coronal to the CEJ of the tooth and bonding the sutures in position with flowable composite. -‐‑Cutting the ends of the sutures using blade so there are no exposed sharp ends. -‐‑Insertion of graft material inside the tunnel and position as coronally as possible. -‐‑Secure the graft in position with sutures. -‐‑Approximation and suture of the initial access vertical incision(s). -‐‑Removal of the sutures 3 weeks post-‐‑surgically. -‐‑Patients were prescribed antibiotics (Amoxicillin or clindamycin), naproxen sodium 550 mg every 12 hours when needed and Chlorhexidine rinse 0.12% twice a day for three weeks. All the surgeries were performed by the same operator, HZ. The optical scanning and digital analysis were performed by a different examiner, AG, from the operator. C-‐‑Digital Image Analysis Alginate impressions were taken at pre-‐‑ and post-‐‑therapy periods and poured in dental stone. The study models were scanned with an optical scanner (3-‐‑Shape, D850) and saved in STL format. The STL files were imported into a reverse engineering software (Geomagic Control). Quantitative analysis of digitized study casts was performed by a single examiner (AG). Pre-‐‑ and post-‐‑operative digitized images were initially cropped, superimposed and then the difference in volume was subtracted (image subtraction). 16 This allowed for the measurement of any changes in the surface area, contour, volume, shape, that occurred following root coverage surgery with VISTA technique. The measurements performed included changes in the location of the gingival zenith, gingival contour and thickness, exposed root surface and root prominence. D-‐‑Outcome variables The outcome variables being measured were initial recession depth, linear height gain in the denuded root surface, initial gingival thickness, and initial root prominence. The outcome measurements were percentage of root coverage, complete root coverage, 3-‐‑D gingival volumetric gain, and gingival thickness gain at 1, 2, 3, 4, and 5 mm from the final gingival margin The changes in soft tissue volume, soft tissue thickness, as well as percentage of root coverage were calculated, reported as mean+SD, and compared with each of the outcome variables being measured: -‐‑Recession Class according to Miller Classification: Recession Class I-‐‑II and Class III (The reason why recession type I and II were part of the same group is because through the digital analysis, the exact location of the mucogingival junction is not clear enough in order to make a distinction. Therefore, both type of recession were analyzed as the same group) -‐‑Tooth type: incisors, canines, premolars and molars -‐‑Pre-‐‑operative root prominence -‐‑Initial gingival margin thickness -‐‑Initial recession depth -‐‑Type of graft material: autogenous connective tissue from palate or tuberosity, acellular dermal matrix (ADM; Perioderm) allograft or xenogenic collagen matrix (XCM; Mucograft) -‐‑Anatomic location of the tooth: maxillary vs mandibular F-‐‑Statistical Analysis: Descriptive statistics were calculated for all variables of interest. Continuous measures were summarized using means and standard deviations whereas categorical measures were summarized using counts and percentages. A nonparametric regression analyses were run using the methods of Brunner and Langer, comparing the outcomes of interest to predictors adjusting for the correlation among observations taken on same patient. All analyses were carried out using SAS Version 9.3 (SAS Institute, Cary, NC, USA). 17 8-‐‑Results A-‐‑Periodontal root coverage with VISTA Figure 1 illustrates the steps in the surgical treatment of a representative patient Figure 1: Illustration of a representative case with the different steps of the VISTA surgical procedure. A) Recession Class III B) Vertical incision C) Subperiosteal tunnel elevation D) Etching E) Coronal suturing with flowable composite F) Connective tissue graft stabilization G) Suture vertical incision H) 12 month results Patient presented with generalized Miller class III gingival recession defects in the maxillary anterior region (Figure 1A). Scaling and root planning was performed to remove all mineralized and non-‐‑mineralized biofilm from the treated teeth, followed by odontoplasty to flatten excessive root prominence in cervical areas and application of EDTA gel for 3 minutes. A vertical incision was placed in the vestibular fornix at the midline, remote from the recession areas (Figure 1B) followed by subperiosteal tunnel elevation extending from the vestibule to the gingival margin and interproximally (Figure 1C). A single loop monofilament suture was placed approximately 3 mm apical to the gingival margin and coronal surfaces of treated teeth were etched for 10 secs (Figure 1D). Coronally repositioning of each gingival margin was done at least 2 mm coronal to the CEJ of the tooth and bonded by sutures in position with flowable composite (Figure 1E). Subepithelial connective tissue graft was harvested from the palate and inserted inside the tunnel and positioned as coronally as possible (Figure 1F). The graft was secured in position with sutures and the initial access vertical incision was sutured (Figure 1G). Sutures were removed 3 weeks post-‐‑surgically. Clinical results after 12 months showed complete root coverage (Figure 1H). B-‐‑Digital image analysis and quantitation Alginate impressions were taken at pre- and post-therapy periods and poured in dental stone. The study models were scanned with an optical model scanner (3-‐‑Shape, D850) and saved in STL format. (Figure 2) 18 Figure 2: Illustration of the stone study cast (A) scanned with the 3 Shape optical scanner (B) to produce an STL file. The STL files were imported into a reverse engineering software (Geomagic Control). (Figure 3) Figure 3: The pre and post-‐‑operative STL files were transferred into Geomagic Control Pre-‐‑ and post-‐‑operative digitized images were initially cropped in order to facilitate image manipulation. This step was performed by cropping the image one tooth adjacent to the treated tooth, using the “Trim” tool from the “Tool Bar”. (Figure 4) Figure 4: Illustration of the trimming process of the digitized study models. Pre-‐‑operative (A) and post-‐‑operative (B) 3-‐‑D study models were trimmed (C) to limit the file size to the region of interest. Cropped pre-‐‑operative (D) and post-‐‑operative (E) 3-‐‑D study models are shown 19 The images were then aligned using solid landmarks on teeth such as cusp tips, marginal ridges or incisal edges, using semi-‐‑automatic alignment tool, namely the “N-‐‑ point alignment” tool (Figure 5A, B). After superimposition, the “Boolean” tool was utilized to excise the volume that was different between the pre-‐‑ and post-‐‑operative digitized images (Figures 5C, D). The region was further cropped to limit analysis to the denuded area that was covered post-‐‑operative by the graft (Figure 5E). Figure 5: Illustration of the steps involved in the superimposition of pre-‐‑ and post-‐‑operative images and cropping of the volume of interest. Pre-‐‑ and post-‐‑operative images were aligned using the semi-‐‑automatic N-‐‑point alignment tool (A, B). The volume change between pre-‐‑ and post-‐‑operative images was detected and cropped (C, D). The volume was further cropped to limit to the volume present over the pre-‐‑existing recession area (E). This allows for the measurement of any changes in the surface area, contour, volume, shape, which occurred following root coverage surgery with VISTA. The measurements performed included changes in the location of the gingival zenith, gingival contour and thickness, exposed root surface and root prominence. C-‐‑Description of parameters measured: The initial recession depth (Figure 6) was calculated by performing a linear measurement from the identifiable CEJ of the tooth to the most apical location of the gingival margin (zenith) in the recession area. The digital software was able to identify the CEJ in all of the cases. If there was a restoration, the margin of the restoration was used as the reference. Figure 6: Illustration of pre-‐‑operative digitized study model and the landmarks used for linear measurement of initial recession depth. 20 The linear root coverage height gain was calculated by two different methods. The first method entailed superimposing the pre-‐‑ and post-‐‑operative scanned study models and using subtraction imaging. This provided us with a 3 dimensional volume that was covering the previously denuded root surface (Figure 7A). Linear measurement along the long axis of the tooth was performed to calculate the linear height gain in the recession after surgery. The second method consisted of a sagittal cut of the superimposed pre-‐‑ and post-‐‑operative volumes to generate a 2-‐‑dimensional image (Figure 7B). Comparison of the values obtained by the two methods demonstrated coincidence of the numbers with less than 2% difference between the measurements. Figure 7: Illustration of linear height gain measurement using 3-‐‑dimensional volume occupying the previously denuded root surface (A) and 2-‐‑dimensional section of super-‐‑imposed pre-‐‑ and post-‐‑operative models (B). The initial gingival margin thickness was calculated by drawing two lines perpendicular to the tooth surface: one at the gingival margin and another at 1mm apical to the gingival margin. The horizontal distance between two lines was used for the measurement of the pre-‐‑operative gingival margin thickness (Figure 8). Figure 8: Illustration of pre-‐‑operative gingival margin thickness and landmarks used for that measurement. The 3 dimensional sagittal section taken at the midfacial area of the tooth with recession defect (A) was used for making a 2-‐‑ dimensional cross-‐‑section (B). The initial root prominence (Figure 9) was calculated by taking an axial section perpendicular to the facial aspect of the tooth at the apical-‐‑most position of the CEJ. A straight line is created from the emergence point of the tooth from the gingival margins on the mesial and distal aspect. The horizontal distance between the outer-‐‑ most position on the root and the horizontal line was calculated as root prominence. 21 Figure 9: Illustration of the steps involved in calculating the pre-‐‑operative root prominence The percentage of linear root coverage (Figure 10) was calculated by dividing the linear height gain by the initial recession depth, and then multiplying it by 100. If the linear height gain was superior to the initial recession the percentage root coverage achieved was expressed as more than 100%. This was observed when the final gingival margin was coronal to the CEJ. Figure 10: Illustration of pre and post-‐‑ operative study model, showing 100% root coverage. Gingival volume gain (Figure 11) was calculated by superimposing pre-‐‑ and post-‐‑operative scanned study models and using subtraction imaging. This provided a 3 dimensional soft tissue area that is now covering the previously denuded root surface. By using the Geomagic software tools, the 3-‐‑dimensional volume gained (in mm 3 ) over the previously denuded root surfaces was calculated. Figure 11: Illustration of the 3 dimensional gingival volume gain (including height, width and depth) of the recession area. 22 The gingival thickness gain (Figure 12) was calculated at different location relative to the post-‐‑operative gingival margin. More specifically they were calculated at 1, 2, 3, 4, and 5 mm relative to the post-‐‑operative gingival margin at the center of the long axis of the tooth. The thickness gain was calculated by superimposing the pre-‐‑ and post-‐‑operative scanned study models and using subtraction imaging. The resultant image shows the outer outline of the pre-‐‑operative and post-‐‑operative soft tissues. Figure 12: Illustration of the 2 dimensional sagittal view of the gingival thickness gain at the 5 different locations relative to the position of the post-‐‑operative gingival margin D-‐‑Quantitative analysis of soft tissue changes: The clinical characteristics of sites with gingival recession and the outcomes achieved are shown in Table 1. Number of recession defects for recession type, tooth type, graft type and anatomic location are shown in Table 2. Results demonstrated a mean percentage of root coverage after 12 months of 92.0 ± 15.0 % for all groups, 102.0 ± 10.0 % for Miller Class I/II and 83.0 ± 14.0 % for Class III recession defects. Complete root coverage was achieved in 42.0 % of all sites, while 71.0% of Miller Class I/II and 16.0% of Miller Class III sites treated yielded complete root coverage. Mean gingival volume gain was 4.8 ± 5 mm 3 for all sites, 3.8 ± 1.8 mm 3 for Class I/II and 5.9 ± 6.9 mm 3 for Miller class III sites. The data in Figure 13 revealed that Miller class I/II sites (total of 42 sites) yielded 102.0 ± 10.0 % root coverage and Miller Class III recession defects (total of 44 sites) exhibited 83.0 ± 14.0% root coverage. The difference between the two groups was statistically significant (p=0.0001). Figure 14 illustrates the comparison of volumetric gain achieved for Miller class I-‐‑II (42 sites) vs. class III (44 sites) gingival recession defects. The data revealed mean gingival volume gain was 4.8 ± 5 mm 3 , 3.8 ± 1.8 mm 3 and 5.9 ± 6.9 mm 3 for both groups, Class I/II, and III, respectively. The difference between the groups was not statistically significant. 23 Figure 15 depicts the comparison of gingival thickness gain at different locations relative to the post-‐‑operative gingival margin of Miller class I-‐‑II (N=42 sites) and class III (N=44 sites) gingival recession defects. When examining mean gingival thickness gain at various locations (1, 2, 3, 4, 5 mm apical to buccal/labial gingival zenith) in all groups, the thickness gain was 1.0 ± 0.3 mm, 1.0 ± 0.4mm, 0.9 ± 0.4 mm, 0.9 ± 0.4 mm and 0.8 ± 0.4 mm at 1, 2, 3, 4, 5 mm, respectively. The thickness gain was statistically significant, when comparing among different locations. The thickness gain was significantly higher at 1 and 2 mm compared to 3, 4, and 5 mm relative to the post-‐‑ operative gingival margin. (p=0.02). In comparing the degree of gingival thickness gain achieved between Miller class I/II versus class III recession defects, at 1 mm apical to the gingival margin there was a statistically significant difference. (p=0.01) Figures 16, 17 and 18 illustrate the root coverage, gingival volume and thickness gain achieved for teeth in different anatomic locations. There were 12 incisors, 17 canines, 38 premolars and 19 molars analyzed. The type of tooth (anterior vs posterior) showed a statistically significant difference on % of root coverage, (p=0.0001) achieved, with incisors having higher percentage root coverage than either molars or premolars. Canines exhibited higher percentage of root coverage than molars. Premolars showed higher percentage root coverage than molars. (Figure 16) The difference between the teeth groups was not statistically significant in terms of gingival volume gain (Figure 17) and gingival thickness gain. (Figure 18) The results in Figure 19 show that root prominence exhibited a statistically significant negative correlation with percentage root coverage (p=0.0001). Sites with higher initial root prominence resulted in lower percentage of root coverage. There was no correlation between pre-‐‑operative root prominence and gingival volume gain nor gingival thickness gain. (Figures 20 and 21) Pre-‐‑operative gingival margin thickness (Figure 22) showed a statistically significant positive correlation with % of root coverage (p=0.0001). There was no statistically significant correlation between pre-‐‑operative gingival margin thickness and gingival volume gain. (Figure 23) Figure 24 illustrates the correlation between initial linear recession depth and percentage root coverage achieved. Initial recession depth showed no statistically significant correlation with percentage of root coverage. On the other hand, initial recession depth showed a statistically significant correlation with gingival volume gain. (Figure 25; p=0.0001) The type of graft material used (palatal CTG (19), tuberosity CTG (33), ADM (26), XCM (8)) did not appear to have any statistically significant correlation with any of the parameters examined. (Figures 26, 27, 28) Figures 29 and 30 depict the comparison of different anatomical tooth locations (maxillary (42) vs mandibular (44)) with the outcome measurements. There was no statistical significant difference in any of the parameters evaluated. 24 9-‐‑Discussion The present study was undertaken to examine the outcome of periodontal root coverage for the treatment of gingival recession defects using VISTA. Quantitative comparison of study casts taken at pre-‐‑ and post-‐‑treatment time points showed the influence of pre-‐‑treatment site characteristics and graft material used on therapy outcomes. This study revealed a number of important observations, including: 1) Application of VISTA for the treatment of multiple recession defects achieved periodontal root coverage and gingival thickness and volume gain 2) Specific initial site characteristics such as root prominence, gingival thickness, type of recession and tooth type demonstrated predictive value on the outcome of periodontal root coverage achieved. Although clinicians intuitively recognize the negative predictive value of root prominence on achieving root coverage, the present study represents the first study to concrete data to demonstrate its predictive value. 3) Initial recession depth and root prominence showed predictive value on achieving gingival thickness and volume gain. 4) The type of graft material used or anatomical location of teeth did not show statistical difference in achieving periodontal root coverage. 5) 3-‐‑D volumetric analysis may be used to detect quantitative changes of soft tissues achieved following periodontal root coverage procedure. Three-‐‑dimensional volumetric analysis has only been applied to a limited degree for examination of soft and hard tissue changes (Fickl et al., 2009, Thoma et al., 2010, Schneider et al., 2011, Rebele et al., 2014). These investigations have demonstrated the benefits of this technology as a quantitative tool with versatile capabilities. Though additional work needs to be done to take full benefit of all of this technology, some of the advantages of 3D analysis include: (Schneider et al., 2014): -‐‑digital measurements on study models offer the advantage of better accessibility to the relevant area. -‐‑measurements can be performed in a nonclinical environment without time constraints. -‐‑measurements can be repeated as many times as needed with the use of various tools, possibly not suitable for intraoral application. -‐‑digital models can be measured in different magnifications and angles. -‐‑digital rulers with high accuracy can be used for measurements of distances, areas, and volumes. The study by Schneider et al., in 2014 was the first to compare digital measurement method to intraoral clinical measurement for different periodontal parameters. It demonstrated that digital measurements of papilla height and amount of gingiva were more reproducible compared with clinical intraoral measurements by different investigators as well as by repeated measurements of the same investigator. 25 This type of measuring method has also been used in a randomized clinical trial (Rebele et al., 2014) for the purpose of studying healing dynamics and evaluating the outcome of surgical root coverage. The present study also performed 3D volumetric assessment of study casts to examine post-‐‑therapy changes in gingival margin position and gingival contour, as well as their relationship to individual risk factors. Classically, gingival augmentation outcomes have been assessed by a periodontal probe. The advantages of this method include low cost and simplicity of the technique. On the other hand, the assessment of outcomes with a periodontal probe has a number of limitations, which include: 1) A stent will be required to ensure measurements are made in same area and direction 2) Probes have markings that measure at best at 1 mm interval, limiting the measurement accuracy 3) The angle at which the operator views the probe can potentially affect the recording accuracy 4) Probe measures vertical or horizontal linear changes of gingival margin, whereas gingival margin is irregular shape and linear changes do not accurately represent changes accomplished after therapy 5) Periodontal probes only record changes in gingival margin, so that changes in surface contour, in particular beyond the gingival margin are not detected. Three-‐‑dimensional quantitation of soft tissue changes provides opportunity to examine many of the parameters, which could not have been possible to measure with a periodontal probe. These include, determination of root surface area, gain of tissue thickness at various depth in the gingiva, surface contour changes, as well as detection of root prominence. The percentage of root coverage achieved in the present study for all groups was 92.0 ± 15%. Interestingly, 102.0 ± 10% root coverage was achieved for Miller class I/II recession defects and 83 ± 14% for Class III sites. The high degree of root coverage achieved, which was sometimes higher than 100%, was possible because VISTA allows coronally advancing the gingival margins of teeth beyond the CEJ and maintaining such position during the healing by coronal anchoring of sutures. The significance of coronally advancing the gingival margin during surgery at least 2 mm past the CEJ has been demonstrated (Pini Prato et al., 2005), where 100% complete root coverage was achieved only in cases where the gingival margin was advanced 2 mm past the CEJ. This implies that after the healing process, such gingival margin can even stay coronal to the CEJ, thus obtaining root coverage over 100%. This was achieved in the majority of class I/II gingival recession defected treated in this study. 26 Moreover, for gingival recession class III sites, where loss of interproximal bone and attachment exists, previous studies have demonstrated that the percentage of root coverage is around 60% (Barker et al., 2010, Carney et al., 2012). This occurs due to the limited blood supply to the area having reduced bone and attachment apparatus. Tunneling procedures, including VISTA, do not utilize surface incisions, in an effort to preserve the vascular supply to the gingival margin. On the other hand, the tremendous coronal advancement of the mucogingival complex and fixation with coronally-‐‑bonded sutures allows for a new coronal establishment of the gingival margin that when provided enough thickness and adequate blood supply, can remain in place and cover compromised recession defects. These results are corroborated by publications reporting that the treatment of gingival recession class III (Aroca et al., 2010, Cairo et al., 2012, Henriquez et al., 2010), can be successfully achieved when coronal advanced flap is performed and the interdental bone and attachment loss is not advanced. The 3D quantitation of surface contour used in the present study provided a number of advantages afforded by volumetric analysis. This 3D analysis enabled quantitation of volume gain achieved by soft tissue augmentation. The mean volume gain was 3.8 ± 1.8 mm 3 and 5.9 ± 6.9 mm 3 for Class I/II, and III sites, respectively. These results may be difficult to interpret in terms of the clinical relevance of each specific volumetric gain. However, volumetric gain can be a great research tool to assess the influence of various risk factors, including initial site characteristics or the type of graft and technique used. These results may be used for future comparison with other related publications. Accordingly, the gingival thickness gain was examined at different locations from the reference point (at 1, 2, 3, 4, 5 mm from the final gingival margin). In all of the surgeries a graft was placed, therefore expecting to achieve increased gingival thickness post operatively. Gingival thickness gain was approximately 1 mm at the most coronal portion and decreased slightly in more apical areas. This can be explained by the fact that the coronal most areas were previously denuded and are likely to gain the most thickness due to the coronal position of the graft. In view of the fact that the present study only considered the outer contour of pre-‐‑ and post-‐‑operative tissues, the degree of soft tissue thickness gain is likely to have been under-‐‑estimated in the present analysis. This is because root prominences where reduced by odontoplasty, which was not detected in the present analysis. We have planned future studies using CBCT to include the root surfaces in the analysis. In terms of recession type, the results of this study correlate with other publications on root coverage (Chambrone et al., 2015), where statistical significant difference in root coverage have been reported between Miller class I/II versus Miller class III gingival recession defects. The presence of interproximal periodontal attachment provides the required vascular supply to support the survival of a gingival graft. Recessions with no interdental tissue loss typically yield better root coverage 27 outcomes (Miller et al., 1985). Nevertheless, as mentioned earlier, the efficacy of root coverage on recession class III was shown in the present study to be predictable. Root convexity is a site-‐‑related factor that per se might influence the clinical outcome of root coverage procedures. (Wennstrom et al., 2003) Experienced clinicians realize that root prominence is an important risk factor in achieving complete root coverage. On the basis of their experience, some authors have stressed the importance of reducing root convexity to enhance the outcome of root coverage procedures. However, scientific data supporting these considerations is lacking, due to the difficulty in its assessment. The literature shows data on dental crown morphology and measurements (Merz et al., 1991), but there is no information regarding root curvature at the cemento-‐‑enamel junction. (CEJ) The part of the root that is outside of the gingival housing can be considered as root prominence (Saletta et al., 2005). Sometimes this curvature is so prominent, that the tension applied to the coronal margin of the flap to be adapted to the curved root surface, may compromise the blood supply to this area. This factor should be accounted for pre operatively and, if needed, root odontoplasty should be performed accordingly to reduce the excessive root surface area. Another consideration as to why root prominence can adversely affect root coverage is that, the more prominent the root, the further is the height of contour of the root from the periodontal ligament source. Optical scanning with digital analysis can be useful for this purpose. This allows us to calculate and quantify the initial root prominence and correlate it with the percentage of root coverage, and gingival thickness/volume gain. Interestingly the data showed a very strong negative correlation between root prominence and root coverage. When the initial root prominence was over 1.3 mm, the percentage of root coverage was reduced substantially. When this prominence was less than 1 mm, root coverage was very predictable. A classification system of different degrees of root prominence should be developed, in an effort to provide a guideline as to how much root odontoplasty to perform. The majority of the RCTs published about mucogingival surgery for root coverage purposes focus on maxillary canines and premolars. (Buti et al., 2013) Specifically to other tooth types, the effect of treatment on mandibular incisors and posterior teeth has also been studied, (Harris et al., 2003, Zucchelli et al., 2012) with positive results (mean root coverage around 90%) However, there is lack of sufficient prospective studies in the literature showing the differences in outcome depending on the tooth type. The present study has shown that tooth type may be an important predictive factor for root coverage. Anterior teeth (central and lateral incisors) were the teeth that 28 showed greater root coverage, followed by canines and premolars. The teeth that presented the least root coverage were the molars. This could be explained by the increased surface area and the increased root curvature. Molars are wider teeth than incisors, so the amount of denuded root that is needed to cover will always be greater than that of an incisor. (Saletta et al., 2005) Also, the curvature of the roots of molars is greater than incisors, therefore limiting the coronal advancement and stability of the graft. Several studies have correlated greater flap thickness to better clinical outcomes after root coverage (Baldi et al., 1999, Berlucchi et al., 2005) and thus identified flap thickness as one relevant prognostic factor in the treatment of gingival recession defects. (Huang et al., 2006) Additional thickening of the marginal gingiva with the use of autologous connective tissue grafts (CTG) can enhance treatment outcomes. There is uniformed agreement that a thick gingival biotype will benefit the outcome of root coverage surgery. (Huang et al., 2006). Nevertheless, very few studies have focused on the single effect of the pre-‐‑operative gingival margin thickness on root coverage alone. (Ahmedbeyli et al., 2014) In the present study, the initial gingival thickness showed a strong positive correlation with root coverage. When the pre-‐‑operative gingival margin thickness was more than 1 mm, 100% root coverage was very predictable. When the initial thickness was less than one mm, decreased root coverage was observed, especially in those cases where interproximal attachment had been lost. This could be explained by understanding the vascular supply to the surgery area. The areas that show thicker biotype can benefit from an increased blood supply that can nourish the graft and the recipient bed. In cases where such blood supply is compromised (Miller Class III recession defects) the initial thickness can become an important predictive factor. The importance of the initial recession depth has also been reported in the literature. Berlucchi et al., in 1999 showed that when presenting recession depth was <4 mm, the mean root coverage was 94.7% and when the presenting recession depth was >4 mm the mean root coverage only reached 85%. According to what is published, it is logical to think that the deeper the recession the more surface area it requires to be covered and the harder it is to obtain complete root coverage. Surprisingly, the present study showed no statistical significance between initial recession depth and percentage of root coverage. It seems that the coronal displacement with stabilization through bonded sutures may help in covering deep recession defects. Nevertheless, these results should be interpreted with caution due to the fact of the limited number of recession defects deeper than 4 mm and the number of variables included in the study. 29 Different types of graft material (autogenous, acellular dermal matrix and xenogenic collagen matrix) were used in the study. There was no statistically significant correlation with any of the parameters analyzed. This result differs from what has been published, where the gold standard is considered CTG + CAF (Buti et al., 2013, Chambrone et al., 2015). In our study, the use of different graft materials did not affect root coverage, gingival thickness or volume gain. There seemed to be a small clinical difference in terms of gingival volume and thickness gain favoring the use of tuberosity graft but the results do not reach statistical significance. These results should be interpreted with caution because the lack of correlation could be related to the sample size and number of variables analyzed in the study. When maxillary and mandibular sites are compared, there is a trend showing positive results in favor of maxillary teeth. It was reported that significantly greater improvements of recession depth were observed for maxillary multiple recession defects treated with SCTG + CAF compared with alike mandibular defects. (Chambrone et al 2006-‐‑ 50) The muscle pull and the decreased thickness of the gingiva in this area could negatively affect the outcome of our mucogingival surgery. The results of this study may have showed a different tendency. There was no statistical significant difference between the different anatomical location of the teeth and the outcome parameters measured. When coronally advanced, the tunnel is tension free because of the advanced periosteal release of the tunnel. In this way, this may allow for less pull of the lip and muscles as would happen with other classical techniques, which could potentially hamper the success of the coronal advancement. The present investigation had a series of limitations, which included: 1) The difficulty of identifying the CEJ in some of the cases, especially if the teeth presented with full contour restorations. In these cases, the restoration margin was used as the reference for measurement. 2) The mucogingival junction was not readily discernable on study models to allow distinction between type I and type II recession defects. This is why both classes were combined as one during data collection and analysis. 3)The use of alginate material as the impression material has its limitations. The volumetric changes that can occur from the moment of the alginate impression until the pouring of the stone cast models, can affect the accuracy and reliability of the results. 4)Besides the infrastructural requirements, training, and expenses, intraoral scanning can be limited in terms of access to the relevant area. Inability to access the area of measurement, unfavorable tooth position, excess or lack of impression material can result in inferior image quality and inability of the software to stitch the images correctly. For example, this is the reason why the interproximal papilla height could not be calculated for this study, due to the fact that the optical scanner could not accurately reproduce the morphology of each papillae in order to be able to make correct analysis. 30 5) The fact that this study was retrospective and without control group does not allow for definitive conclusions about causality. 6) The influence of the multiple variables on each outcome variable analyzed in this study was not accounted for. This may act as a confounding variable in the assessment of our observations, data analysis and statistical significance of our results. Conclusions should not be drawn from those variables that did not reach statistical significance since there were no controls to compare them to. The implications of the present data for the future studies include: 1) randomized control clinical trials will be required in order to examine the efficacy of VISTA and validate the risk factors identified in this study. 2) Digital measurements have to be compared with conventional clinical measurements to validate these measurements. 3) If the risk factors identified in the present study are validated in future randomized control clinical trials, these factors can be incorporated as part of risk assessment to predict outcome of therapy. 4) The risk factors (root prominence, interproximal periodontal attachment loss, initial gingival margin thickness, tooth type) may potentially be incorporated into a classification system to predict clinical outcomes. 31 10-‐‑Conclusion The present pilot retrospective study demonstrated that 3D volumetric analysis provided a highly quantitative tool for examination of soft tissue changes and associated risk factors for the treatment of gingival recession defects. The results of this study suggested that root prominence was an important negative predictor of root coverage. Additional predictors of outcome included tooth type (incisor, canine, premolar or molar), interproximal tissue loss (Miller class I/II vs III) and pre-‐‑operative gingival margin thickness. The present data utilizing VISTA provided data, which compare favorably to published reports for the treatment of multiple recession defects. Randomized controlled clinical trial will be required to compare the efficacy of VISTA to other periodontal root coverage methods, as well as to examine the predictive value of the risk factors identified in the present study. 32 11-‐‑Bibliography Ahmedbeyli, C., Ipci, S. D., Cakar, G., Kuru, B. E. & Yilmaz, S. (2014) Clinical evaluation of coronally advanced flap with or without acellular dermal matrix graft on complete defect coverage for the treatment of multiple gingival recessions with thin tissue biotype. 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Minimally Invasive Treatment of Maxillary Anterior Gingival Recession Defects by Vestibular Incision Subperiosteal Tunnel Access and Platelet-‐‑ Derived Growth Factor BB.Int J Periodontics Restorative Dent 2011;31:653–660 Zucchelli G, De Sanctis M. Treatment of multiple recession-‐‑type defects in patients with esthetics demands. J Periodontol. 2000;71:1506–14 Zucchelli G, Marzadori M, Mele M, Stefanini M, Montebugnoli L. Root coverage in molar teeth: A comparative controlled randomized clinical trial. J Clin Periodontol 2012;39:1082-‐‑1088. Zucchelli G, Mele M, Mazzotti C, Marzadori M, Montebugnoli L, De Sanctis M. Coronally advanced flap with and without vertical releasing incisions for the treatment of multiple gingival recessions: A comparative controlled randomized clinical trial. J Periodontol 2009;80:1083-‐‑1094 Zuhr, O., Rebele, S. F., Schneider, D., Jung, R. E. & Hurzeler, M. B. (2014b) Tunnel technique with connective tissue graft versus coronally advanced flap with enamel matrix derivative for root coverage: a RCT using 3D digital measuring methods. Part I. Clinical and patient centered outcomes. Journal of Clinical Periodontology 41, 582– 592. 37 12-‐‑Tables/Figures Miller Class IRD %RC CRC RP GVG IGMT I-II 2 ± 0.6 102 ± 10 71 0.6 ± 0.3 3.8 ± 1.8 1 ± 0.2 III 2.5 ± 1 83 ± 14 16 1.2 ± 0.7 5.9 ± 6.9 0.8 ± 0.2 All 2.3 ± 0.9 92 ± 15 42 0.9 ± 0.6 4.8 ± 5 0.9 ± 0.2 Miller Class GT1 GT2 GT3 GT4 GT5 I-II 0.9 ± 0.3 1 ± 0.3 0.9 ± 0.3 0.9 ± 0.3 0.9 ± 0.3 III 1.1 ± 0.4 1.1 ± 0.5 0.9 ± 0.4 0.9 ± 0.4 0.8 ± 0.5 All 1 ± 0.3 1 ± 0.4 0.9 ± 0.4 0.9 ± 0.4 0.8 ± 0.4 Table 1: Characteristics of defect sites and associated outcomes -‐‑IRD = Initial recession depth -‐‑% RC = Percentage of Root coverage -‐‑CRC: Complete root coverage -‐‑RP = root prominence -‐‑GVG =Gingival volumetric gain -‐‑IGMT=Initial gingival margin thickness -‐‑GT: Gingival thickness gain at the different locations (1,2,3,4,5mm) from the post-‐‑operative gingival margin Table 2: Number of recession defects for recession type, tooth type, graft type and anatomic location: 1) Number of class I/II and III defects 2) Number of incisors, canines, premolars, and molars 3) Number of teeth for each graft material 4) Number of maxillary and mandibular teeth Column1 Column2 1-Recession type Class I,II 42 Class III 44 Total 86 2-Tooth type Incisors 12 Canines 17 Premolars 38 Molars 19 Total 86 3-Graft type Palate 19 Tuberosity 33 ADM 26 XCM 8 Total 86 4-Anatomic location Maxillary 42 Mandibular 44 Total 86 38 Figure 13: Comparison of % root coverage achieved for Miller class I-‐‑II (42 sites) vs. class III (44 sites) gingival recession defects. * P<0.001 Figure 14: Comparison of volumetric gain achieved for Miller class I-‐‑II (42 sites) vs. class III (44) gingival recession defects. Difference between groups was not statistically significant. 3.8 5.9 0 2 4 6 8 10 12 14 Class/I1II Class/III Volumetric/Gain/(mm3) Recession/type/according/to/Miller/Classification 39 Figure 15: Comparison of gingival thickness gain at different locations relative to the post-‐‑ operative gingival margin of Miller class I-‐‑II (42 sites) and class III (44 sites) gingival recession defects. * P<0.01 Figure 16: Comparison of % root coverage achieved for teeth in different anatomic locations (12 incisors, 17 canines, 38 premolars,19 molars). * P<0.001 40 Figure 17: Comparison of gingival volumetric gain for teeth in different anatomic locations. (12 incisors, 17 canines, 38 premolars,19 molars). Differences among groups were not statistically significant. Figure 18: Comparison of gingival thickness gain achieved at different locations relative to the post-‐‑operative gingival margins for teeth in various anatomic locations (12 incisors, 17 canines, 38 premolars,19 molars). * P<0.05 4.24 7.21 4.22 4.25 0 2 4 6 8 10 12 14 16 18 Incisors Canines Premolars Molars Gingival;Volumetric;Gain;(mm3) Type;of;Tooth 41 Figure 19: Scatter plot illustrating the correlation between pre-‐‑operative root prominence and percentage root coverage achieved. R 2 = -‐‑0.77; p<0.001. Figure 20: Scatter plot illustrating the correlation between pre-‐‑operative root prominence and gingival volume gain achieved. R 2 = -‐‑0.008; p>0.05. 50 60 70 80 90 100 110 120 130 140 +0.5 0 0.5 1 1.5 2 2.5 3 %.root.coverage Pre+operative.Root.Prominence 0 5 10 15 20 25 30 35 &0.5 0 0.5 1 1.5 2 2.5 3 Gingival/volumetric/gain/(mm3) Pre&operative/Root/Prominence 42 Figure 21: Scatter plot illustrating the correlation between pre-‐‑operative root prominence and gingival thickness gain at 1-‐‑5mm intervals relative to the post-‐‑ operative gingival margin. 1mm: R 2 =0.11; p>0.05. 2mm: R 2 = -‐‑0.16; p>0.05. 3mm: R 2 = -‐‑0.21; p<0.01. 4mm: R 2 = -‐‑0.21; p>0.05. 5mm: R 2 = -‐‑0.24; p>0.05. Figure 22: Scatter plot illustrating the correlation between initial gingival marginal thickness and percentage root coverage achieved. R 2 = 0.71; p<0.001. 0 20 40 60 80 100 120 140 160 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 %)Root)Coverage Initial)Gingival)Margin)Thickness 43 Figure 23: Scatter plot illustrating the correlation between initial gingival marginal thickness and gingival volume gain. R 2 = -‐‑0.01; P>0.05. Figures 24: Scatter plot illustrating the correlation between initial linear recession depth and percentage root coverage achieved. R 2 = -‐‑0.17; p>0.05. 0 5 10 15 20 25 30 35 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 Gingival1Volume1Gain1(mm3) Initial1Gingival1Margin1Thickness 0 20 40 60 80 100 120 140 160 0 1 2 3 4 5 6 7 %+Root+Coverage Initial+Recession+Depth 44 Figures 25: Scatter plot illustrating the correlation between initial linear recession depth and gingival volume gain. R 2 = 0.71; p<0.001. Figure 26: Degree of root coverage achieved for soft tissue augmentation procedures using various graft material (Palate 19, Tuberosity 33, ADM 26, XCM 8) Comparisons among different groups were not statistically significant. 0 5 10 15 20 25 30 35 0 1 2 3 4 5 6 7 Gingival0Volume0Gain0(mm3) Initial0Recession0Depth 94 99 97 82 0 20 40 60 80 100 120 140 XCM Palate Tuberosity ADM %<Root<Coverage Type<of<Graft 45 Figure 27: Gingival volume gain achieved for soft tissue augmentation procedures using various graft material (Palate 19, Tuberosity 33, ADM 26, XCM 8). Comparisons among different groups were not statistically significant. Figure 28: Gingival thickness gain achieved at different locations from post-‐‑operative gingival margin for soft tissue augmentation procedures using various graft material (Palate 19, Tuberosity 33, ADM 26, XCM 8). Comparisons among different groups were not statistically significant. 4.22 2.94 4.07 6.52 0 2 4 6 8 10 12 14 XCM Palate Tuberosity ADM GingivalAVolumeAGainA(mm3) TypeAofAGraft 1.16 1.04 0.94 0.96 1.02 0.86 0.94 0.84 0.81 0.74 1.15 1.26 1.03 0.99 1.02 0.94 0.85 0.8 0.85 0.88 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 1 2 3 4 5 Gingival3Thickness3Gain3 Location3of3analysis3relative3to3postA operative3gingival3margin3between3different3Types3of3Graft XCM Pal Tuber ADM 46 Figure 29: Comparison of % root coverage achieved for teeth in different anatomic locations (maxillary 42, mandibular 44). The difference between two groups was not statistically significant. Figure 30: Comparison of gingival volume gain achieved for teeth in different anatomic locations (maxillary 42, mandibular 44). The difference between two groups was not statistically significant. 92 92 0 20 40 60 80 100 120 Maxillary Mandibular %4Root4Coverage 3.8 5.8 0 2 4 6 8 10 12 Maxillary Mandibular Gingival8Volume8Gain8(mm3)

Asset Metadata

Creator Gil, Alfonso (author)

Core Title Three-dimensional volumetric analysis of gingival augmentation for the treatment of multiple recession defects by vestibular incision subperiosteal tunnel acces (VISTA)

Contributor Electronically uploaded by the author (provenance)

School School of Dentistry

Degree Master of Science

Degree Program Periodontology / Craniofacial Biology

Publication Date 07/21/2016

Defense Date 05/12/2016

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag connective tissue graft,gingival recession,mucogingival surgery,OAI-PMH Harvest,periodontal regeneration,periodontal root coverage

Format application/pdf (imt)

Language English

Advisor Zadeh, Homa (committee chair), Kar, Kian (committee member), Paine, Michael (committee member)

Creator Email alfonslg@usc.edu,gil.alfon@hotmail.com

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c40-272385

Unique identifier UC11280063

Identifier etd-GilAlfonso-4574.pdf (filename),usctheses-c40-272385 (legacy record id)

Legacy Identifier etd-GilAlfonso-4574.pdf

Dmrecord 272385

Document Type Thesis

Format application/pdf (imt)

Rights Gil, Alfonso

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the a...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus MC 2810, 3434 South Grand Avenue, 2nd Floor, Los Angeles, California 90089-2810, USA

Abstract (if available)

Abstract Aim: Treatment of multiple contiguous recession defects, in particular in sites with interproximal periodontal attachment loss remains a clinical challenge. Vestibular Incision Subperiosteal Tunnel Access (VISTA) has been developed as a technique well suited for these clinical scenarios. The present study sought to analyze retrospective data on patients treated with VISTA to achieve periodontal root coverage for the treatment of multiple contiguous recession defects. The aim of this study was to determine the efficacy of VISTA for root coverage and gingival thickness/volume gain, and to determine the role of various risk factors (initial root prominence, initial gingival margin thickness, initial recession depth, recession type, tooth type, graft type and anatomic location). ❧ Material and methods: Thirteen patients with 86 teeth exhibiting multiple gingival recession defects (mean initial recession 2.3 mm±0.9) were treated with VISTA using various graft materials. Treated root surfaces were thoroughly debrided with scaling and root planning. Odontoplasty was performed to reduce root prominence, and exposed root surfaces were conditioned with EDTA. VISTA entailed a vertical incision in the vestibule, through which a subperiosteal tunnel was created, extending towards the vestibular depth and gingival margins. The tunnel was coronally advanced and stabilized with sutures that were bonded to the facial surface of the teeth. Graft material included autogenous connective tissue from palate/tuberosity, acellular dermal matrix (ADM