Techniques on vertical ridge augmentation: Indications and effectiveness.

Vertical ridge augmentation techniques have been advocated to enable restoring function and esthetics by means of implant-supported rehabilitation. There are three major modalities. The first is guided bone regeneration, based on the principle of compartmentalization by means of using a barrier membrane, which has been demonstrated to be technically demanding with regard to soft tissue management. This requisite is also applicable in the case of the second modality of bone block grafts. Nonetheless, space creation and maintenance are provided by the solid nature of the graft. The third modality of distraction osteogenesis is also a valid and faster approach. Nonetheless, owing to this technique's inherent shortcomings, this method is currently deprecated. The purpose of this review is to shed light on the state-of-the-art of the different modalities described for vertical ridge augmentation, including the indications, the step-by-step approach, and the effectiveness.

Vertical bone augmentation utilizing a titanium-reinforced PTFE mesh: A multi-variate analysis of influencing factors.

OBJECTIVE: To clinically evaluate the use of a titanium-reinforced PTFE mesh for vertical bone augmentation (VBA) of deficient alveolar ridges. MATERIALS AND METHODS: This case series documented consecutive patients treated for VBA with a newly developed PTFE mesh. VBA was performed in anterior and posterior, maxillary and mandibular arches using anorganic bovine bone combined with autogenous graft in a 1:1 ratio. Healing time from initial surgery to re-opening was recorded. Baseline vertical deficiency, absolute bone gain (gross height gained), and relative gain (percentage of defect fill with respect to the baseline deficiency) were registered. RESULTS: Fifty-seven patients (65 defects) were included in the analysis. The mean baseline vertical deficiency was 5.5 ± 2.6 mm. The mean absolute bone gain was 5.2 ± 2.4 mm. A relative gain of 96.5 ± 13.9% was achieved. Overall, 89.2% of cases showed complete regeneration, which occurred in all sites with baseline deficiencies of <5 mm, in 95.6% of sites with 5-8 mm deficiencies, and in 89.4% of sites with >8 mm deficiencies. Each 1-mm addition to the baseline height deficiency increased the likelihood of incomplete bone regeneration by 2.5 times. Defect location had a statistically significant but a limited clinical impact on the bone height gained (<0.5 mm). Complications were observed in three cases (3%). CONCLUSIONS: Vertical bone augmentation with titanium-reinforced PTFE mesh and a mixture of autologous bone and xenograft is a safe and predictable procedure. The extent of the baseline vertical deficiency influences the percentage of bone gained.

Long-term crestal bone changes in implants placed in augmented sinuses with minimal or moderate remaining alveolar bone: A 10-year retrospective case-series study.

OBJECTIVES: To evaluate long-term clinical and radiographic outcomes of dental implants placed after lateral window sinus augmentation utilizing the sagittal sandwich technique. MATERIALS AND METHODS: Patients treated with sinus augmentation were included in this retrospective case-series study. The surgical procedure was performed with particulate autogenous bone- and anorganic bovine bone-derived mineral (3:7 ratio). Implants were grouped based on baseline residual alveolar ridge height: group S (residual alveolar ridge height of 0.1-3.5 mm), group M (height of 3.5-7mm), and group C (native bone). Radiographs were taken at baseline (abutment installation) and annually throughout the 10-year follow-up. RESULTS: A total of 86 patients (92 sinus lifts) and 209 implants were included. Ten sinus membrane perforations were recorded (11% incidence), and graft infections occurred in 3 cases (3.2% incidence). During the 10-year follow-up, 3 implants (1.4%) failed. No significant differences in the mean implant marginal bone loss (MBL) between the three groups were found after 1-, 2-, and 5-year follow-up (p > .05). At 10 years, group C exhibited more MBL than group M with a mean difference of -0.53 mm (p = .01). After 10 years, MK III implants displayed significantly more bone loss in native bone than those in augmented bone with a mean difference of 0.48 mm (p = .02). Five patients and 7 implants developed peri-implantitis with no significant differences between the groups (p = .570). CONCLUSION: Implant placement after two-stage sinus grafting utilizing the sagittal sandwich technique is a relatively safe and predictable procedure with minimal complications and MBL after 10-year follow-up.

Effectiveness of vertical ridge augmentation interventions: A systematic review and meta-analysis.

AIM: The primary aim of this systematic review was to evaluate the effect of various techniques used for vertical ridge augmentation on clinical vertical bone gain. MATERIAL AND METHODS: A protocol was developed to answer the following focused question: "In patients with vertical alveolar ridge deficiencies, how effective are different augmentation procedures for clinical alveolar ridge gain?" Randomized and controlled clinical trials and prospective and retrospective case series were included, and meta-analyses were performed to evaluate vertical bone gain based on the type of procedure and to compare bone gains in controlled studies. RESULTS: Thirty-six publications were included. Results demonstrated a significant vertical bone gain for all treatment approaches (n = 33; weighted mean effect = 4.16 mm; 95% CI 3.72-4.61; p < 0.001). Clinical vertical bone gain and complications rate varied among the different procedures, with a weighted mean gain of 8.04 mm and complications rate of 47.3% for distraction osteogenesis, 4.18 mm and 12.1% for guided bone regeneration (GBR), and 3.46 mm and 23.9% for bone blocks. In comparative studies, GBR achieved a significant greater bone gain when compared to bone blocks (n = 3; weighted mean difference = 1.34 mm; 95% CI 0.76-1.91; p < 0.001). CONCLUSIONS: Vertical ridge augmentation is a feasible and effective therapy for the reconstruction of deficient alveolar ridges, although complications are common.

A multicenter randomized controlled trial using a novel collagen membrane for guided bone regeneration at dehisced single implant sites: Outcome at prosthetic delivery and at 1-year follow-up.

OBJECTIVES: To compare clinical performance of a novel resorbable non-cross-linked collagen membrane (CXP) with a reference membrane (non-cross-linked resorbable membrane; BG) for simultaneous implant placement and guided bone regeneration (GBR) at dehisced single implant sites. MATERIALS AND METHODS: Preliminary data from this randomized controlled trial were reported previously; this is the 12-month report. The primary outcome measure was defected height at 6 months post-GBR. Secondary outcomes included implant cumulative survival rate (CSR) and success rate since placement; bone level changes, pink esthetic score (PES), and patient satisfaction since definitive prosthesis delivery; patient quality of life since pretreatment; and the 1-year bleeding index. Non-parametric statistical analyses were performed. RESULTS: Among patients, 24 were treated with CXP and 25 with BG. The 1-year implant CSR and success rate were 100% (n = 42). Bone level change between definitive prosthetic delivery and 1 year was not significantly different between the CXP and BG groups (BG + 0.42 mm, CXP + 0.01 mm). The PES increased from 7.55 to 8.10 for the CXP group and from 6.48 to 7.48 for the BG group; 1-year bleeding indices were 0 (16 CXP, 18 BG) and 1 (4 CXP, 2 BG). Patient quality of life changed from an OHIP-14 score of 6.5 at pretreatment to 1.9 at 1 year. Overall satisfaction (visual analogue score) with function and esthetics was 9.9 and 9.7, respectively. Inter-group differences were not significant for assessed outcomes. No device-related adverse events were reported. CONCLUSIONS: The use of CXP and BG for simultaneous implant placement and GBR at dehisced implant sites similarly reduced defect height and improved secondary measures, indicating non-inferiority.

Prognostic Classification System for Implant Recession Defects.

PURPOSE: The etiology and progression of periimplant mucogingival defects are multifactorial. As such, the aim of this study was to discern and discuss the key long-term prognostic factors that change the balance of homeostasis/regeneration in periimplant mucogingival and recession defects. MATERIALS AND METHODS: This report provides cases and a discussion of anatomical factors that affect the long-term maintenance of periimplant soft tissue. RESULTS: The factors guiding long-term maintenance of the periimplant soft tissue apparatus are increasingly complex due to the additive combination of patient-related factors, anatomical variations, and unique material-host interactions. CONCLUSIONS: Severity and number of these contributing factors should be considered before implant placement and/or in the treatment of periimplant defects to achieve the best esthetic and functional outcome. In addition, assessment of prognostic factors should be used to provide the patient a realistic, long-term assessment of the esthetic and functional stability of both implant and the surrounding periimplant tissues.

Decision Tree for Reconstructive Treatment of Peri-implantitis Defects.

Peri-implantitis, a common complication among patients receiving implant-supported restorative therapy, often requires surgical intervention for effective treatment. Understanding the specific configuration of peri-implant bony defect and adjacent bone peaks is crucial for tailoring treatment strategies and improving outcomes. A decision tree for reconstructive peri-implantitis therapy has been developed based on the new classification of defect configurations (Class I to V), guiding clinicians in selecting treatment options, including biomaterials, techniques, and healing approaches. Furthermore, clinicians are encouraged to consider various factors such as local predisposing factors (such as soft tissue characteristics, prosthetic design, and implant position in three-dimensional perspective), clinical factors (surgeon skill and experience), and patient-related factors (such as local and systemic health, preferences, and cost) when evaluating reconstructive therapy options.

Management of the Lingual Flap During Vertical Augmentation of the Atrophic Anterior Mandible: Anatomical Overview and Description of the Technique.

Vertical ridge augmentation in the anterior mandible is a technically delicate procedure that requires knowledge of some anatomical structures to reduce intra- and postoperative complications. Proper soft tissue management is one of the primary aspects to the success of these techniques, enabling tension-free primary wound closure and preventing membrane exposure. This cadaveric and clinical study provides an anatomical overview of the lingual portion of the anterior mandible. Moreover, there is a description of a novel surgical approach for release of the lingual flap that will help clinicians achieve primary closure without incurring intrasurgical complications.

The Clinical Relevance of the Lingual Branch in Ridge Augmentation of the Posterior Mandible: A Pilot Cadaver Study.

Guided bone regeneration (GBR) requires a tension-free flap without damaging the collateral circulation in order to secure better surgical outcomes. Topographic knowledge regarding the neurovascular bundles in the posterior aspect of the mandible can prevent complications during lingual flap design. The lingual branch (LB) of the inferior alveolar or maxillary arteries is not sufficiently illustrated or described in the literature. Nevertheless, it has an intimate relationship with the lingual nerve (LN) during ridge augmentation and implant-related posterior mandible surgery. Therefore, this study aimed to clarify the morphology and topography of the LB related to GBR surgeries. In the present human cadaveric study, the LB was analyzed in 12 hemimandibles using latex injection and corrosion casting. Two types of LB were identified based on their origin and course. The LB was found in a common connective tissue sheath close to the LN. The LB assembled several anastomoses on the posterior lingual aspect of the mandible and retromolar area. The LB acted as an anatomical landmark in identifying LN at the posterior lingual aspect of the mandible.

The influence of vertical ridge augmentation techniques on peri-implant bone loss: A systematic review and meta-analysis.

INTRODUCTION: The primary aim of this systematic review was to investigate and compare the outcomes of different vertical ridge augmentation (VRA) techniques in relation to peri-implant bone loss (PBL), after at least 12 months of functional loading. MATERIAL AND METHODS: The search was conducted to find all the studies about VRA and measurements of PBL with at least 12 months follow-up. Three pairwise meta-analysis (MA) was performed to completely evaluate the outcomes. RESULTS: A total of 42 studies were included, of which 11 were randomized clinical trials (RCTs). RCTs were available only for guided bone regeneration (GBR), onlay, and inlay techniques. The weighted mean estimate (WME) of PBL value was found to be 1.38 mm (95% confidence interval [95% CI]: 1.10-1.66) after a mean follow-up of 41.0 ± 27.8 months. GBR, Inlay, Onlay, osteodistraction, and SBB represented in weight 32.9%, 30.6%, 25.0%, 7.6%, and 3.9%, respectively; and their WME (95% CI) were 1.06 (0.87-1.26) mm, 1.72 (1.00-2.43) mm, 1.31 (0.87-1.75) mm, 1.81 (0.87-1.75) mm, and 0.66 (0.55-0.77) mm, respectively. Among the secondary outcomes, the analysis was conducted for vertical bone gain, healing complication rate, surgical complication rate, implant survival, and success rate. CONCLUSIONS: The primary findings of the meta-analysis, based on the changes between final and baseline values, showed that the peri-implant bone loss could be influenced by the type of intervention but there is a need to evaluate in RCTs the behavior of the peri-implant bone levels after long-term follow-up for all techniques.

Elucidating the Benefit of Perforated vs Non-Perforated Membranes in Guided Bone Regeneration: An in Vivo Histologic Evaluation and Histomorphometric Analysis.

Background: Non-perforated Polytetrafluoroethylene (PTFE) membranes are effectively utilized in guided bone regeneration (GBR) but may hinder cell migration due to limited interaction with the periosteum. This study compared bone regeneration using occlusive or perforated membranes combined with acellular collagen sponge (ACS) and recombinant human bone morphogenic protein-2 (rhBMP-2) in a canine mandibular model. Material and Methods: Male beagle dogs (n=3) received two mandibular defects each to compare ACS/rhBMP-2 with experimental (perforated group) and control (non-perforated group) membranes (n=3 defects/group). Tissue healing was assessed histomorphologically, histomorphometrically and through volumetric reconstruction using microcomputed tomography. Results: The perforated group showed increased bone formation and reduced soft tissue formation compared to the non-perforated group. For the primary outcome, histomorphometric analysis revealed significantly greater total regenerated bone in the perforated group (67.08 ± 6.86%) relative to the nonperforated group (25.18 ± 22.44%) (p = 0.036). Perforated membranes had less soft tissue infiltration (32.91 ± 6.86%) compared to non-perforated membranes (74.82 ± 22.44%) (p = 0.036). Conclusion: The increased permeability of membranes in the perforated group potentially enabled periosteal precursor cells greater accessibility to rhBMP-2. The availability may have accelerated their differentiation into mature bone-forming cells, contributing to the stimulation of new bone production, relative to the non-perforated group.

Influence of residual pockets on periodontal tooth loss: A retrospective analysis.

BACKGROUND: Individuals enrolled in supportive periodontal therapy (SPT) can still present with tooth loss due to periodontitis (TLP). There is limited evidence on the influence of residual pockets (RPc) and a defined "threshold" at which a patient's profile is set to be at high risk for TLP in the literature. Therefore, this study aimed to assess the influence of RPc on TLP and determine the prognostic performance of RPc compared to the staging and grading of periodontitis on TLP risk. METHODS: Clinical data from 168 patients (3869 teeth) treated for periodontitis and receiving SPT for at least 10 years were evaluated in this retrospective study. TLP and the percentage of sites with RPc ≥ 5 mm or ≥6 mm per patient were collected. The prognostic performance of RPc was compared to the staging and grading of the disease on TLP using a multilevel Cox proportional hazard regression model. RESULTS: Over a median follow-up of 25 years, 13.7% of teeth were lost, 4.6% of which were due to periodontitis. Most patients with TLP had ≥1 site with RPc ≥5 mm (90.8%) or ≥6 mm (77.6%). Multivariate multilevel Cox regression revealed that patients with >15% of sites with RPc ≥5 mm had a hazard ratio of 2.34, and grade C had a hazard ratio of 4.6 for TLP compared to RPc ≤4 mm/grade A. Grading exhibited the best discrimination and model fit. CONCLUSION: Patients with RPc ≥5 mm at >15% of the sites are at risk for tooth loss. Grading and RPc ≥5 mm displayed very good predictive capability of TLP.

Hard- and Soft-Tissue Reconstruction in the Anterior Maxilla for Esthetic Implant Therapy.

Implant rehabilitation in the esthetic zone is often challenged by vertical bone defects and soft-tissue deformities. This article describes a combined hard- and soft-tissue restorative approach that involves staged guided bone regeneration, implant placement, and two soft-tissue augmentation procedures to achieve optimal esthetic outcomes at multiple implant sites in the anterior zone. The staged bone augmentation procedure, performed with a mixture of autogenous and xenogeneic bone graft and a nonresorbable membrane, allowed for the placement of three implants in ideal positions after 9 months. Further soft-tissue augmentation involved the use of multiple connective tissue grafts (CTGs) stabilized on the occlusal aspect of the implants and between the implants to enhance peri-implant papillae (ie, the "iceberg" CTG approach). Then, a second soft-tissue grafting procedure was executed to reposition the mucogingival junction and re-establish an adequate amount of keratinized mucosa at the implant sites. The article highlights the importance of performing both hard- and soft-tissue augmentation for implant therapy in the esthetic zone.

Papilla reconstruction using a vertical interproximal tunnel approach.

INTRODUCTION: Papilla reformation is one of the most difficult and elusive surgical techniques for clinicians. Although it involves similar tenets to those applied for soft tissue grafting at recession defects, crafting a small tissue in restricted space remains unpredictable. Numerous grafting techniques have been developed to correct interproximal and buccal recession, but so far, only a limited number of techniques have been prescribed for interproximal remediation. CASE PRESENTATION: This report describes in detail a modern technique (the vertical interproximal tunnel approach) for reforming the interproximal papilla and treating interproximal recession. It also documents three challenging cases of papilla loss. The first case presented Class II papilla loss and a recession type 3 gingival defect adjacent to a dental implant, managed using the vertical interproximal tunnel approach through a short vertical incision. A 6-mm increase in attachment level and almost complete papilla fill were observed in this case with this surgical technique for papilla reconstruction. The second and third cases presented Class II papilla loss between two adjacent teeth, managed using the vertical interproximal tunnel approach through a semilunar incision and achieving full papilla reconstruction. CONCLUSION: Both described incision designs for the vertical interproximal tunnel approach require technical meticulousness. When executed carefully and using the most beneficial pattern of blood supply, predictable reconstruction of the interproximal papilla can be achieved. It also helps alleviate concerns associated with inadequate flap thickness, blood supply and flap retraction.

The "Iceberg" Connective Tissue Graft Technique for Peri-implant Papilla Augmentation Following Interproximal Bone Reconstruction.

Implants with deficient papillae and black triangle are common findings. The treatment of these esthetic complications is considered challenging, and with limited predictability. Therefore, the aim of the present report is to describe a novel technique for papilla augmentation (the "Iceberg" connective tissue graft [iCTG]) after extraction and interproximal bone reconstruction in the anterior region. A 35-year-old patient presented with a hopeless tooth with interproximal clinical attachment loss extending up the apical third of the adjacent tooth. Interproximal bone reconstruction was performed through alveolar ridge preservation by directly applying recombinant human platelet-derived growth factor-BB (rhPDGF-BB) to the exposed root surface of the adjacent tooth. A mixture of autogenous bone chips (obtained from the ramus) and bovine bone xenograft particles, previously mixed with the growth factor, was also used. The patient was able to come back for implant therapy only 2 years later. An incomplete regeneration of the interproximal bone was observed. Therefore, to compensate the interproximal deficiency, the iCTG approach, involving a double layer CTG with different origins, was utilized. Two small grafts from the tuberosity were sutured to the mesial and distal ends of a wider CTG harvested from the palate, aiming at gaining additional volume at the interproximal sites. The composite graft was then sutured on top of the implant platform, with the flap that was then released and closed by primary intention. After conditioning of the peri-implant tissues, the case was finalized with a satisfactory outcome. The described iCTG could be an effective approach for reconstructing peri-implant papilla following interproximal bone reconstruction.

Facial Mucosal Level Change Following Maxillary Anterior Single Immediate Tooth Replacement in Extraction Sockets With Facial Bone Wall Defects: A 4- to 15-Year Retrospective Study.

An intact extraction socket has been considered a prerequisite for an immediate implant placement and provisionalization (IIPP) procedure. Recent studies, however, have shown successful outcomes when IIPP was performed in sockets with a facial bone wall defect. This retrospective study evaluated the facial implant mucosal stability following IIPP in extraction sockets with a facial bone wall defect in the esthetic zone. The study included 16 cases in 16 patients who received maxillary anterior single IIPP with contour bone graft (C-BG) and contour connective tissue graft (C-CTG) in compromised extraction sockets (V- or U-shaped defect). After a mean follow-up of 6 years, the implant success rate was 100% (16/16). Minimal and non-statistically significant changes were noted in the facial implant mucosal and marginal bone level. Statistically significant changes were observed in facial implant mucosal thickness gain (2.5 mm [1.8 mm to 3.5 mm]) and midfacial bone sounding reduction (6 mm). Within the confines of this study, IIPP with simultaneous C-BG and C-CTG in fresh extraction sockets exhibiting a V- or U-shaped facial bone wall defect can lead to long-term successful outcomes in terms of mucosal stability, contour bone gain, and marginal bone level stability.

Periosteum Classification and Flap Advancement Techniques Around the Mental Foramen.

Various surgical flap advancement techniques for bone regeneration have been described in the literature; however, the clinical challenges of managing tissue that contains scars or embedded foreign materials have not been thoroughly described, especially around metal foramen. Fibrotic and thickened scar periosteum as well as mental foramen restrict the tissue from responding in the same way as native tissue. Therefore, additional considerations and approaches must be considered to achieve tension-free flap closure. This article presents a flap advancement classification that describes three common clinical scenarios based on the periosteum and soft tissue quality and provides surgical approaches for tissue management in each classification, with a focus on flap advancement around the mental foramen.

Simultaneous Alveolar Ridge Augmentation and Periodontal Regenerative Therapy Leveraging Recombinant Human Platelet-Derived Growth Factor-BB (rhPDGF-BB): A Case Report.

Severe alveolar ridge deficiencies in concomitance with periodontal attachment loss can represent a serious clinical challenge in the context of implant therapy. The present case report describes the management of a complex defect in the esthetic zone via ridge augmentation and periodontal regenerative therapy using a biologic material. A systemically healthy 55-year-old man diagnosed with peri-implantitis around an implant in the maxillary left central incisor position and with severe bone loss on the mesial aspect of the maxillary left lateral incisor underwent several surgical interventions to achieve simultaneous vertical ridge augmentation and periodontal regeneration. These interventions included implant removal, bone augmentation using a composite bone graft (autogenous bone + xenograft particles), and a bioactive protein (recombinant human platelet-derived growth factor), soft tissue augmentation using connective tissue grafts, and peri-implant keratinized mucosa width augmentation via a labial gingival graft strip and a xenogeneic collagen matrix. Substantial gains in vertical bone and clinical attachment were achieved, which allowed for delayed implant placement and subsequent completion of tooth replacement therapy with an implant-supported prosthesis. The present case report demonstrates how simultaneous vertical ridge augmentation and periodontal regeneration can be achieved to manage a challenging clinical situation. Key factors to consider in this type of scenario are proximal bone level, tooth mobility, surgical flap design and management, biomaterial selection, and proper treatment sequencing.

Horizontal guided bone regeneration on knife-edge ridges: A retrospective case-control pilot study comparing two surgical techniques.

INTRODUCTION: Studies evaluating guided bone regeneration (GBR) on knife-edge ridges using absorbable membranes with staged approaches have reported various horizontal bone gains. This study compared the horizontal bone gain obtained via a conventional technique of GBR and a recently-reported technique. Bone loss during the healing process was also measured. METHODS: Consecutive patients who underwent GBR on knife-edge ridges via a conventional technique (control group) or the Sausage Technique (test group) were included in this study. GBR was performed using a collagen membrane and deproteinized bovine bone mineral combined with an autogenous graft at a 1:1 ratio. Cone-beam computed tomography (CBCT) was performed preoperatively, postoperatively, and after the patient healed. Horizontal bone width was measured on CBCT images 2 mm apical from the top of the crest. The preoperative CBCT and posthealing CBCT were superimposed to calculate the bone gain after healing, and the preoperative and postoperative CBCT scans were superimposed to calculate the bone gain after surgery. Bone loss during healing was calculated by subtracting the width of the ridge after healing from the postoperative width. RESULTS: The mean horizontal bone gain was significantly lower in the control group (2.7 ± 1.8 mm; 83.2%) than in the test group (5.3 ± 2.3 mm; 216.8%) (p = 0.003). The average horizontal bone loss between regeneration and implant placement was 0.9 mm in the control group (27.9%) and 2.1 mm in the test group (29.4%). While the absolute bone loss was significantly different (p = 0.012), the percentage of bone resorption was not (p = 0.608). CONCLUSION: The new technique resulted in significantly more bone gain than a conventional GBR technique. The rate of graft resorption during healing was stable regardless of the amount of grafted material.

Prevalence and risk indicators of midfacial peri-implant soft tissue dehiscence at single site in the esthetic zone: A cross-sectional clinical and ultrasonographic study.

BACKGROUND: Esthetic complications of dental implants in the esthetic zone can have a major negative impact on patients' quality of life and perception of implant therapy. The aim of the present study was to evaluate the prevalence of peri-implant soft tissue dehiscence (PSTD) and the clinical and ultrasonographic risk indicators for this condition. METHODS: Subjects with ≥1 healthy single dental implants in the esthetic area were identified and recruited. Clinical and ultrasonographic measurements, including PSTD class and subclass, probing depth, keratinized mucosa width (KMW), mucosal thickness (MT) at 1 mm and 3 mm, buccal bone distance (BBD) and buccal bone thickness, were evaluated in healthy implants and implants with PSTD. RESULTS: A total of 153 subjects with a total of 176 dental implants were included. The prevalence of PSTD was 54.2% and 56.8% on a patient and implant level, respectively. The most frequent type of PSTD was the one characterized by having both an implant-supported crown longer than the clinical crown of the homologous tooth and a visible abutment/implant fixture exposed to the oral cavity. The multivariate analysis showed that the presence of an adjacent implant, a longer time of the implant in function, limited MT, reduced KMW, and increased BBD were significantly associated with the presence of PSTD. CONCLUSIONS: PSTDs are common findings in the esthetic region. Several risk indicators for this condition, such as presence of an adjacent implant, increased time in function of the implant, higher BBD, lower KMW, and MT were identified.