Autogenous graft versus collagen matrices for peri-implant soft tissue augmentation. A systematic review and network meta-analysis.

OBJECTIVE: The primary objective of this review is to compare autogenous soft tissue grafts (connective tissue graft - CTG and free gingival graft-FGG) with different type of matrices (acellular dermal matrix-ADM, xenograft collagen matrix-XCM, volume-stable collagen matrix-VCMX) used to increase peri-implant soft tissues. MATERIALS AND METHODS: A search on electronic databases was performed to identify randomized and non-randomized controlled trials (RCTs and CCTs, respectively) with either parallel or split-mouth design, and treating ≥ 10 patients. A network meta-analysis (NMA) was used to compare different matrices. Soft tissue thickness dimensional changes and keratinized width (KMW) changes were the primary outcome measures. The secondary outcomes were to evaluate: a) PROMs; b) volumetric changes; c) surgical operating time; and d) different periodontal measurements. RESULTS: A total of 23 studies were included in the qualitative analysis, and 16 studies (11 RCTs and 5 CCTs) in the quantitative analysis. A total of N = 573 sites were evaluated for NMA. CTG resulted the best material for increasing peri-implant soft tissue thickness, at 180 and 360 days after surgery. The use of an ADM showed good results for buccal thickness increase, primarily in the first three months after surgery. Vestibuloplasty + FGG resulted in the most effective technique for peri-implant KMW augmentation, after 180 days. CONCLUSIONS: While CTG demonstrated better performance in all the comparison and FGG showed to be the best graft to increase keratinized mucosa up to 90 days, ADM and VCMX may be used to increase soft tissue horizontal thickness with lower patients' morbidity. LIMITATIONS: The limits of this NMA are the following: a) limited number of included studies; b) high heterogeneity among them (number of patients, treatment sites, surgical techniques, outcome measures, and follow-ups). CLINICAL RELEVANCE: Many studies compared the efficacy of autogenous and non-autogenous grafts in terms of gingival thickness, volume, and keratinized width increase. However, there is still not clear overall evidence on this topic. This NMA helps clinicians to choose the right material in different peri-implant soft tissue procedures. Recommendations for future studies are mandatory.

A comparison of alveolar ridge mucosa thickness in completely edentulous patients.

PURPOSE: The purpose of this cross-sectional clinical study was to determine and compare alveolar ridge mucosa thickness at crestal, buccal, and lingual locations of the maxillary and mandibular arches in completely edentulous patients using a dedicated, ultrasonic gingival scanner. MATERIALS AND METHODS: Thirty-eight completely edentulous subjects were included in the study. In each subject, soft tissue thickness was measured at 28 sites of the edentulous ridge by a single calibrated examiner. Intra-observer reliability was calculated with Intraclass Correlation Coefficients by measuring 10 subjects twice, after 1 week. Measurements (mm) were taken at the buccal, lingual, and crestal aspects of the ridge with a dedicated ultrasonic scanner. Repeated measures ANOVA and paired t-tests were used to compare the mean buccal, lingual, and crestal soft tissue thicknesses at each site. The Generalized Estimating Equations model was used to study the effects of age, sex, and race. Confidence level was set to 95%. RESULTS: Mean tissue thickness ranged from 0.96  to 1.98 mm with a mean of 1.63 ± 0.25 mm. Intraclass Correlation Coefficients were > 0.97. No significant differences between buccal, crestal, and lingual sites were noted for the mandibular arch as well as at 4 sites on the maxillary arch (maxillary right second molar, maxillary right canine, maxillary left first premolar, maxillary left second molar). However, significant differences in soft tissue thickness were noted for all remaining maxillary sites. Race was found to be positively correlated with tissue thickness, with Black individuals showing a significantly greater thickness than White individuals at 4 sites (maxillary right first molar, maxillary left canine, mandibular right second premolar, mandibular right first molar). Age was found to be positively correlated with tissue thickness at 4 sites (maxillary left central incisor, maxillary left first molar, maxillary left second molar, mandibular left second premolar) and negatively correlated at 2 sites (mandibular right canine, mandibular right second molar). Female sex was positively (maxillary left second premolar, maxillary left second molar) and negatively (mandibular right canine) correlated, respectively, with tissue thickness at 3 sites. When data for anterior and posterior sites were respectively pooled, tissue thickness was significantly less at anterior sextant lingual and crestal sites, while no difference was seen for buccal sites. CONCLUSION: Statistically significant differences for alveolar ridge mucosa thickness were found at several sites in the maxilla and between anterior and posterior sextants for lingual and crestal sites in the maxillary and mandibular arches. Tissue thickness differences were also noted for race with Black individuals showing greater tissue thickness at some sites. Age and sex did not show a clear effect on tissue thickness. Recorded differences in tissue thickness were however small and appear of uncertain clinical significance.

The importance of soft tissue condition in bone regenerative procedures to ensure long-term peri-implant health.

Bone regenerative procedures have been widely proved to be a reliable treatment option to re-create the ideal pre-implant clinical conditions. Nevertheless, these techniques are not free from post-operative complications which might result in implant failure. Consequently, as demonstrated by the increasing recently published evidence, a careful pre- and intra-operative flap evaluation to ensure an ideal and hermetic tension-free wound closure is of paramount importance to successfully treat bony defects. In this respect, several surgical interventions mainly aimed to increase the amount of keratinized mucosa either to allow an optimal healing after a reconstructive procedure or to establish an optimal peri-implant soft tissue seal have been proposed. The present review summarizes the level of evidence on the surgical clinical aspects which have an impact on the soft tissue handling associated with bone reconstructive procedures and on the importance of soft tissue conditions to enhance and maintain peri-implant health in the long-term.

Complications and treatment errors in peri-implant soft tissue management.

Inadequate quality, quantity, or aesthetics of the peri-implant soft tissues can result from a combination of factors related to the outcome of treatments performed before, during, or after implant placement. In this paper, we describe in detail the treatment errors that can pave the way for the onset of mucositis or give rise to soft tissue complications such as peri-implant soft tissue discoloration or dehiscence, graft exposure, or scar formation. By tracing the error back to the planning or surgical stage, clinical insights on surgical soft tissue management are provided to avoid or treat complications that affect the status of the peri-implant soft tissues. Mastering the learning curve and knowing the limitations of each technique are fundamental for preventing added treatment failures that can result in increased patient morbidity and overall discontent.

The effect of triangular cross-section neck design on crestal bone stability in the anterior mandible: A retrospective study with a 5-year follow-up.

OBJECTIVES: The objective of this study, which included a 5-year follow-up, was to compare peri-implant soft tissue health, crestal bone loss (CBL), and buccal bone thickness (BBT) around triangular cross-section neck (TN) or round neck (RN) implants, using cone-beam computed tomography. MATERIALS AND METHODS: This study was initially designed as a prospective 1-year randomized controlled study and then extended with a 5-year retrospective evaluation of clinical and radiographic records. In the initial 1-year study, a total of 20edentulous patients receiving 40 implants with similar diameters were randomly assigned to the RN or TN groups using a split-mouth design. Pocket probing depths (PPD), plaque index (PI), and gingival index (GI) were recorded at postoperative month 12. CBL and BBT at three levels (0, -2, and -4 mm) were evaluated 1 year after insertion. Five years after insertion, PPD, PI, GI, CBL, and BBT were recorded as patients were recalled for clinical and radiographic monitoring. RESULTS: Nineteen patients completed the study. After 5 years, no significant differences in PPD, PI, and GI scores and BBT values between the two groups (p > .05). The mean ± SD CBL values at the final follow-up visit were -0.71 ± 0.69 mm for TN and -1.03 ± 0.86 mm for RN (p < .01). CONCLUSIONS: These results suggest better crestal bone preservation using implants with TN when compared to RN after a 5-year follow-up. However, TN showed similar results to RN regarding peri-implant soft tissue health and BBT.

Clinical performance of immediately placed and immediately loaded single implants in the esthetic zone: A systematic review and meta-analysis.

OBJECTIVES: The aim of this study was to assess the following PIO question: In adult patients treated with an indication for single tooth extraction in the maxillary esthetic zone (15-25), what is the influence of an immediate implant placement and immediate loading protocol on the clinical performance (primary aim) and esthetic outcomes (secondary aim) focusing on investigations published after 2010. MATERIAL AND METHODS: An electronic search in Medline (PubMed), the Cochrane Central Register of Controlled Trials, and EMBASE databases up to April 2022 was performed to identify clinical studies investigating the outcome of single implants subjected to immediate placement with immediate restoration/loading (Type 1A). RESULTS: Sixty-three studies (10 randomized controlled trials, 28 prospective and 25 retrospective cohort studies) were included with a follow-up ranging from 12 to 96 months. One thousand nine hundred sixty-one implants reported survival rates of 99.2 (98.6-99.5) % at 1 year, 97.5 (95.9-98.4) % after 3 years, and 95.8 (93.3-97.4) % after 5 years; 1064 immediately loaded restorations presented survival rates of 98.9 (97.8-99.5) % after 1 year, 96.8 (93.6-98.4) % after 2 years, and 94.8 (89.6-97.4) % after 5 years. Comparing baseline to 12-month data using the Hedges' g effect size (95% CI), papilla height presented an overall effect size of -0.71 (-1.25, -0.1) mm, midfacial recession change of -0.15 (-0.66, 0.36) mm, and a 0.82 (0.37, 1.28) gain in PES. CONCLUSIONS: Immediate implant placement and immediate loading can be considered a predictable and safe treatment option for single maxillary anterior restorations with adequate survival rates and favorable esthetics outcomes for up to 5 years.

Disparity in the Influence of Implant Provisional Materials on Human Gingival Fibroblasts with Different Phases of Cell Settlement: An In Vitro Study.

The development of healthy peri-implant soft tissues is critical to achieving the esthetic and biological success of implant restorations throughout all stages of healing and tissue maturation, starting with provisionalization. The purpose of this study was to investigate the effects of eight different implant provisional materials on human gingival fibroblasts at various stages of cell settlement by examining initial cell attachment, growth, and function. Eight different specimens-bis-acrylic 1 and 2, flowable and bulk-fill composites, self-curing acrylic 1 and 2, milled acrylic, and titanium (Ti) alloy as a control-were fabricated in rectangular plates (n = 3). The condition of human gingival fibroblasts was divided into two groups: those in direct contact with test materials (contact experiment) and those in close proximity to test materials (proximity experiment). The proximity experiment was further divided into three phases: pre-settlement, early settlement, and late settlement. A cell culture insert containing each test plate was placed into a well where the cells were pre-cultured. The number of attached cells, cell proliferation, resistance to detachment, and collagen production were evaluated. In the contact experiment, bis-acrylics and composites showed detrimental effects on cells. The number of cells attached to milled acrylic and self-curing acrylic was relatively high, being approximately 70% and 20-30%, respectively, of that on Ti alloy. There was a significant difference between self-curing acrylic 1 and 2, even with the same curing modality. The cell retention ability also varied considerably among the materials. Although the detrimental effects were mitigated in the proximity experiment compared to the contact experiment, adverse effects on cell growth and collagen production remained significant during all phases of cell settlement for bis-acrylics and flowable composite. Specifically, the early settlement phase was not sufficient to significantly mitigate the material cytotoxicity. The flowable composite was consistently more cytotoxic than the bulk-fill composite. The harmful effects of the provisional materials on gingival fibroblasts vary considerably depending on the curing modality and compositions. Pre-settlement of cells mitigated the harmful effects, implying the susceptibility to material toxicity varies depending on the progress of wound healing and tissue condition. However, cell pre-settlement was not sufficient to fully restore the fibroblastic function to the normal level. Particularly, the adverse effects of bis-acrylics and flowable composite remained significant. Milled and self-curing acrylic exhibited excellent and acceptable biocompatibility, respectively, compared to other materials.

Influence of surface nanotopography and wettability on early phases of peri-implant soft tissue healing: an in-vivo study in dogs.

BACKGROUND: It is well established that nanotopography and wettability of implant surfaces contribute to osseointegration and long-term implant success. However, the effects of a hydrogenated surface with nanotubular and superhydrophilic properties on peri-implant soft tissue remain unclear. This study was designed to study the impact of a modified abutment surface on early soft tissue integration compared with a machined surface. METHODS: Thirty-six implants were placed at the bone level in the bilateral mandible of six beagles, followed by healing abutments belonging to the standard machined Ti-6Al-4V alloy abutments (TC4-M), anodized abutments with nanotubes (TC4-Nano), and hydrogenated abutments (TC4-H/Nano) groups, which were randomly screwed to the implants. After two and four weeks of wound healing, the animals were euthanized for histological evaluation. RESULTS: A superhydrophilic nanotubular surface developed on the hydrogenated abutment. Histological and histometric analyses revealed similar peri-implant soft tissue healing and dimensions for the three types of abutments at two and four weeks. Connective tissue (CT) length was longer around TC4-H/Nano abutments compared with standard abutments; however, the differences were not statistically significant. Moreover, collagen fibers in the TC4-H/Nano group extended and were attached perpendicularly to the superhydrophilic surface. CONCLUSIONS: Our results revealed that the soft tissue interface adjacent to the hydrogenated abutment is comparable to that of the machined abutment. A tendency of increased CT length and perpendicular collagen fibers was observed around the modified abutment. This study suggests that nanotubular/superhydrophilic surfaces could be a promising modification to enhance soft tissue sealing. However, comprehensive studies should be conducted to evaluate the peri-implant soft tissue around the modified abutment immunohistochemically, histopathologically, and clinically.

Soft tissue response to different abutment materials: A controlled and randomized human study using an experimental model.

OBJECTIVES: Aim of this study was to compare the soft tissue response to implant abutments made of titanium, zirconia, zirconia veneered with feldspar ceramics and PEEK by various clinical, histological, microbiological, and molecular biological markers in an experimental model. MATERIALS AND METHODS: A total of 40 experimental one-piece healing abutments of four different materials were mounted on bone level implants in 20 volunteering patients (split-mouth design). After a three-month period of open healing, clinical parameters at the abutments were assessed and adjacent mucosa was sampled for inflammatory cytokine mRNA concentrations and histological analysis by a novel method. In addition, PISF samples were obtained for the analysis of periodonto-pathogenic bacteria counts and active MMP-8 levels. Marginal bone level change was measured by intra oral radiographs. RESULTS: Abutments of the different materials did not exhibit significant differences regarding clinical parameters, pathogenic bacteria counts or pro-inflammatory cytokine concentrations. Likewise, no significant differences were detected regarding soft tissue morphology or bone level change. Compared to titanium abutments, significantly less mononuclear inflammatory cells were detected in the mucosa at abutments made of zirconia veneered with feldspar ceramics. CONCLUSIONS: All examined abutment materials exhibited a similar soft tissue response compared to titanium and histological data did not reveal early signs of elevated inflammation caused by PEEK- and feldspar-veneered zirconia abutments. Due to the short observation period and the small sample size, a final conclusion on the long-term suitability of those abutment materials cannot be drawn. However, based on the presented data, we consider further studies on that subject as appropriate.

Effect of peri-implant mucosal thickness on esthetic outcomes and the efficacy of soft tissue augmentation procedures: Consensus report of group 2 of the SEPA/DGI/OF workshop.

OBJECTIVES: The aim of this study was to comprehensively assess the literature in terms of the effect of peri-implant mucosal thickness on esthetic outcomes and the efficacy of soft tissue augmentation procedures to increase the mucosal thickness with autogenous grafts or soft tissue substitutes. MATERIAL AND METHODS: Two systematic reviews (SR) were performed prior to the consensus meeting to assess the following questions. Review 1, focused question: In systemically healthy patients with an implant-supported fixed prosthesis, what is the influence of thin as compared to thick peri-implant mucosa on esthetic outcomes? Review 2, focused question 1: In systemically healthy humans with at least one dental implant (immediate or staged implant), what is the efficacy of connective tissue graft (CTG), as compared to absence of a soft tissue grafting procedure, in terms of gain in peri-implant soft tissue thickness (STT) reported by randomized controlled clinical trials (RCTs) or controlled clinical trials (CCTs)? Review 2, focused question 2: In systemically healthy humans with at least one dental implant (immediate or staged implant), what is the efficacy of CTG, as compared to soft tissue substitutes, in terms of gain in peri-implant STT reported by RCTs or CCTs? The outcomes of the two SRs, the consensus statements, the clinical implications, and the research recommendations were discussed and subsequently approved at the consensus meeting during the group and plenary sessions. CONCLUSIONS: There was a tendency of superior esthetic outcomes in the presence of a thick mucosa. The connective tissue graft remains the standard of care in terms of increasing mucosa thickness.

The Effects of Abutment Materials on Peri-Implant Soft Tissue Integration: A Study in Minipigs.

PURPOSE: To evaluate, in a minipig model, the soft tissue integration of four different transmucosal materials, as well as the peri-implant bone remodeling. MATERIALS AND METHODS: A total of 40 implants were placed in five minipigs in a single stage surgery, and two of each of the following abutment materials were used in each animal: (1) titanium (Ti; control), (2) polymethylmethacrylate (PMMA), (3) zirconia (Zi), and (4) veneering ceramic (VC). After a healing period of 3 months, the samples were collected and subjected to nondecalcified histology. The soft tissue dimensions (sulcus, junctional epithelium, and connective tissue attachment) were assessed on each abutment and the distance from the implant margin to first bone-to-implant contact (BIC) was measured. RESULTS: The mean biological width-characterized by the sum of junctional epithelium and connective tissue measurements-was 3.8 (0.6) mm and no statistically significant difference was found between the four groups (p = 0.41). However, a long junctional epithelium (3.3-3.8 mm) and a very short connective tissue attachment (0.1-0.2 mm) were observed with all abutments. The measured peri-implant bone remodeling was similar in all four groups (p = 0.88). CONCLUSIONS: Within its limitations, this study showed that all tested materials allowed soft tissue integration, consisting of a long junctional epithelium, extending close to the bone level, and a rather short portion of connective tissue.

An Esthetic Evaluation of Different Abutment Materials in the Anterior Maxilla: A Randomized Controlled Clinical Trial Using a Crossover Design.

PURPOSE: To assess the effect of implant abutment material and soft tissue thickness on the peri-implant soft tissue color using spectrophotometry and to evaluate gingival esthetics and patient satisfaction with three different abutments. MATERIALS AND METHODS: Twenty-five patients with a missing maxillary tooth in the esthetic area received an endosseous implant using a two-stage protocol. Gray titanium, pink anodized titanium, and hybrid zirconia custom abutments were fabricated for each participant and inserted for one week with a cross-over design in a randomized manner. Color measurements were made using a spectrophotometer comparing midfacial peri-implant soft tissue and marginal gingiva of the contralateral tooth. CIE Lab color scale was used following the formula: ΔE = [(∆L)2 + (∆a)2 + (∆b)2 ]½ . PES scores were recorded, and patient satisfaction questionnaires were completed at each abutment change visit and at 1-year follow-up. Statistical analysis was performed using Friedman's test and the Wilcoxon signed-rank test with Bonferroni correction as well as the Mann-Whitney U test (α = 0.05). RESULTS: Abutment material type significantly affected the ΔΕ values of the peri-implant mucosa when compared to the contralateral teeth. At baseline, the highest ΔΕ means ± standard deviation (SD) values were obtained with gray titanium (11.25 ± 2.98), followed by pink anodized titanium (9.90 ± 2.51), and zirconia abutments (6.46 ± 1.43). Differences were statistically significant irrespective of soft tissue thickness. The highest PES values were obtained with zirconia abutments (10.88 ± 0.88), followed by pink anodized titanium (10.12 ± 1.13) and the lowest with gray titanium (9.68 ± 1.41). PES differences were significant only for the thin soft tissue group. Regarding patient satisfaction, VAS scores for the pink anodized and zirconia hybrid abutment groups were higher than the gray titanium group for each question. CONCLUSION: The color difference between soft tissues around teeth and implants was significant in all groups regardless of tissue thickness. The hybrid zirconia abutments resulted in the least color difference, followed by pink anodized and gray titanium. Significantly different PES values were recorded only for the thin tissue group. There was no significant difference in patient satisfaction between zirconia and pink anodized abutments at the 1-year follow up. Pink anodized abutments represent a good esthetic alternative to zirconia hybrid abutments especially in mechanically challenging situations.

Clinical and histological comparison of the soft tissue morphology between zirconia and titanium dental implants under healthy and experimental mucositis conditions-A randomized controlled clinical trial.

OBJECTIVES: To analyse the soft tissue morphology under healthy and experimental mucositis conditions comparing zirconia and titanium implants. METHODS: Forty-two patients with two adjacent missing teeth received one zirconia (Zr) and one titanium (Ti) implant, with the mesial and distal position randomized. At 3 months, half of the patients were instructed to continue (healthy; h) and the other half to omit (experimental mucositis; m) oral hygiene around the implants for 3 weeks. Clinical parameters were evaluated before and after the experimental phase, and a soft tissue biopsy was harvested. Mixed model analyses were performed to analyse the data. RESULTS: The plaque control record increased significantly for the two mucositis groups, reaching 68.3 ± 31.9% (mean ± SD) for Zr-m and 75.0 ± 29.4% for Ti-m (p < .0001), being also significantly lower for Zr-m than for Ti-m. Bleeding on probing remained stable in group Zr-m and amounted to 21.7 ± 23.6%, but increased significantly in group Ti-m (p = .040), measuring 32.5 ± 27.8%. The number of inflammatory cells and the length of the junctional epithelium did not significantly differ between the groups. CONCLUSION: Both implants rendered similar outcomes under healthy conditions. Lower plaque and bleeding scores were detected for zirconia implants under experimental mucositis conditions. Histologically, only minimal differences were observed.

Novel method to obtain human non-separated histological samples for the assessment of peri-implant soft tissue response: A feasibility study.

OBJECTIVES: To introduce a standardized and less invasive clinical model that provides histological information on the abutment-mucosa interface in humans. MATERIALS AND METHODS: New experimental healing abutments were left in an open healing position on bone-level implants in the interforaminal region of the mandibles in six edentulous patients. The one-piece abutments were hollow cylinder-shaped with two lateral openings that allow for ingrowth of the peri-implant mucosa into the central abutment cavity. After three months of healing, abutments and ingrown mucosa were sampled and processed for histological analysis in a non-separated resin-embedding technique. To test the validity of the new model, the ingrown tissue was compared to the peri-implant mucosa around the same samples. RESULTS: None of the experimental abutments exhibited signs of failure, and all samples showed mucosal ingrowth to the inner-abutment cavity. Comparison of ingrown tissue and peri-implant mucosa revealed no significant differences regarding the traits: tissue morphology, quality of collagen fibers, and adherence to the abutment. Ingrown mucosa exhibited a tendency for higher leukocyte infiltration. CONCLUSIONS: The presented model is a promising approach to reduce invasiveness during the sampling process for human non-separated abutment biopsies.

Convergent implant transmucosal collar and healing abutment: aesthetics influence on soft tissues. A clinical study.

Two conditions are necessary for a correct and functional prosthetic implant rehabilitation: maintaining pre-implant soft tissue health and stability of bone tissue, in terms of implant osseous-integration and maintenance of optimal crestal attachment levels. In addition to these parameters - necessary for the longevity of the restoration - one of the main aspects of therapy is the achievement of a final aesthetic that reproduces as faithfully as possible the natural anatomy of the lost tooth and the associated soft tissues. To achieve this last objective, an implant system was designed and used by our group. This implant is characterized by a convergent trans-mucosal emergence fixture associated with a progressive closing system of trans-mucosa healing pillars (healing abutment). This guarantee, together with the micro and macrostructure of the implant, an immediate and highly aesthetic condition of the peri-implant soft tissues, and in the same time an optimal seal on the convergent neck of the implant itself.

The relationship between dental implant papilla and dental implant mucosa around single-tooth implant in the esthetic area: A retrospective study.

OBJECTIVE: The aim of the present study was (a) to evaluate the relationship between dental implant mucosa and dental implant papilla levels; and (b) to identify the clinical parameters associated with peri-implant soft tissue stability over time. MATERIALS AND METHODS: This is a retrospective study on a cohort of patients seeking a single-tooth implant therapy in a private practice in the Paris area. Two independent examiners analyzed photographs and radiographs taken the day of definitive crown load (baseline) and the last follow-up visit (at least 12 months later) in order to measure four peri-implant soft and hard tissue parameters. RESULTS: Seventy-four patients corresponding to 90 implants were analyzed. During a mean follow-up of 53.88 months, five implants (5.6%) presented with an apical displacement of the mid-facial marginal mucosal level of at least 1 mm. Changes in the mid-facial mucosa level were explained by changes in (a) the keratinized tissue height over time (p < .0001); (b) changes in the papilla height (p < .0001); and (c) by the periodontal phenotype (p = .007). A significant difference between papillae that gain in height (n = 85) and papilla that lost height (n = 78) was observed concerning (a) the timing of the implant placement (p = .019); and (b) the presence of an incomplete papilla fill (distance from the top of the papilla to the contact point) at baseline (p = .004). CONCLUSIONS: The present findings indicate a dependent association between dental implant mucosa and dental implant papilla levels. Stability of peri-implant soft tissues depends on periodontal phenotype, keratinized tissue height and papilla height.

Implant Digital Impression in the Esthetic Area.

The aim of this report is to describe two standardized protocols for digital impression when implant support rehabilitation is used in the esthetic area. The two techniques were used to transfer all provisional crown parameters to definitive restorations in different clinical scenarios. In the direct technique, an impression (STL1) is made of the provisional restorations attached to the implants, with surrounding gingival tissue. The second scan (STL2) captures the sulcular aspect of the peri-implant soft tissue immediately after removal of the provisional restoration. The last impression (STL3) of the complete arch is made with a standardized scanbody attached to the implant to capture the 3D location of the implant. The direct technique is indicated when the peri-implant soft tissues are stable upon removal of the provisional restoration. The indirect technique is used when the gingival tissue collapses rapidly after the removal of the provisional crown. The impressions of the provisional restoration and the position of the implant are similar to those obtained with the direct technique, and the shape of the peri-implant tissue is extrapolated from the negative shape obtained from making the digital impression when the provisional restoration is taken out of the mouth. Finally, in both techniques the 3 scans are superimposed to obtain a file, which contains the details of the peri-implant soft tissue. The direct and indirect digital techniques allowed realization of a predictable definitive restoration in the esthetic zone in different clinical scenarios, reducing the duration of clinical procedures.

Influence of abutment material on peri-implant soft tissues in anterior areas with thin gingival biotype: a multicentric prospective study.

PURPOSE: The aim of the present clinical trial was to analyze, through spectrophotometric digital technology, the influence of the abutment material on the color of the peri-implant soft tissue in patients with thin gingival biotype. MATERIAL AND METHODS: Thirty-seven patients received an endosseous dental implant in the anterior maxilla. At time of each definitive prosthesis delivery, an all-ceramic crown has been tried on gold, titanium and zirconia abutment. Peri-implant soft-tissue color has been measured through a spectrophotometer after the insertion of each single abutment. Also facial peri-implant soft-tissue thickness was measured at the level of the implant neck through a caliper. A specific software has been utilized to identify a standardized tissue area and to collect the data before the statistical analysis in Lab* color space. ΔE parameters of the selected abutments were tested for correlation with mucosal thickness. Pearson correlation test was used. RESULTS: Only 15 patients met the study inclusion criteria on peri-implant soft-tissue thickness. Peri-implant soft-tissue color was different from that around natural teeth, no matter which type of restorative material was selected. Measurements regarding all the abutments were above the critical threshold of ΔE 8.74 for intraoral color distinction by the naked eye. The ΔE mean values of gold and zirconium abutments were similar (11.43 and 11.37, respectively) and significantly lower (P = 0.03 and P = 0.04, respectively) than the titanium abutment (13.55). In patients with a facial soft-tissue thickness ≤2 mm, the ΔE mean value of gold and zirconia abutments was significantly lower than that of titanium abutments (P = 0.03 and P = 0.04, respectively) and much more close to the reference threshold of 8.74. CONCLUSIONS: For peri-implant soft tissue of ≤2 mm, gold or zirconia abutments could be selected in anterior areas treatment. Moreover, the thickness of the peri-implant soft tissue seemed to be a crucial factor in the abutment impact on the color of soft tissues with a thickness of ≤2 mm.

Influence of plasma cleaning procedure on the interaction between soft tissue and abutments: a randomized controlled histologic study.

INTRODUCTION: Plasma application can lead to an improved adhesion between soft tissue and abutments and promotes cell spreading. OBJECTIVE: A triple-blinded randomized controlled clinical trial was performed to in vivo test the effect of cleaning abutment titanium surfaces with plasma of argon on cell adhesion and collagen fiber orientation at an early healing time. MATERIAL AND METHODS: Thirty healthy patients with 30 submerged implants, at the second surgery, randomly received either a specially designed abutment with no additional treatment (as they come from industry; control group, G1) or cleaned by plasma of argon (test group, G2). Two weeks thereafter, a small biopsy including abutment and soft tissues around the abutment was performed. Abutments were analyzed using scanning electron microscopy to assess cell adhesion to the abutment surface. Outcome measures were the following: percentage of area occupied by cells, the presence or absence of cells, aspect of adhered cells, and the presence of contaminants. At the same time, the soft tissue histological analysis evaluated density and orientation of collagen fibers. Statistical analysis was performed using the Kolmogorov-Smirnov normality test and Levene variance homogeneity test. Data were analyzed using a nonparametric ranking test. The associations between the different qualitative variables were studied using Pearson's chi-squared test. The Mann-Whitney U-test (for two independent samples) was applied for quantitative variables. RESULTS: Mean percentages of area occupied by cells were 15.14% (range 2.91-44.27) and 33.75% (range 2.37-68.4) for G1 and G2, respectively. Differences were close to significance (P = 0.089). The proportion of samples presenting adhered cells was homogeneous between the two groups (P = 0.142). In all cases, cells presented a flattened aspect, but not in three cases in the G2; in 17 cases, cells were efficiently adhered, and in 11 cases, cells presented filopodia with no statistical differences between groups (P > 0.05). No case from G2 showed contamination with cocobacteria with statistical differences between groups (P = 0.006). Collagen fiber density was higher in the basal, medial, and coronal area of G2 compared to G1 with a statistical difference in the internal area (P < 0.05). The orientation of the fibers varied according to the coordinate area with oblique fibers predominant in G2 than in G1. CONCLUSION: Plasma of argon may promote cell adhesion and positively influence collagen fiber orientation. A greater sample is necessary to confirm these preliminary results.

Expansion of the peri-implant attached gingiva with a three-dimensional collagen matrix in head and neck cancer patients-results from a prospective clinical and histological study.

OBJECTIVES: Attached peri-implant gingiva has proven to have an influence on the long-term stability of dental implants. In patients with head and neck cancer, a functional peri-implant gingiva is even more of critical importance. The aim of the presented prospective study was to investigate a three-dimensional xenogeneic collagen matrix for augmentation around dental implants in patients with former head and neck cancer. MATERIAL AND METHODS: Eight patients presenting with insufficient peri-implant gingiva underwent vestibuloplasty on 51 implants using a xenogeneic collagen matrix. The clinical performance and the shrinking tendency of the matrix were analyzed in a cohort study. Furthermore, eight biopsies from the augmented regions were examined histologically to determine the biomaterial-related tissue reaction. RESULTS: Initially after vestibuloplasty, a mean width of attached gingiva of 4.4 ± 0.94 mm could be achieved. At clinical follow up investigation 6 months after vestibuloplasty, a mean width of 3.9 ± 0.65 mm attached peri-implant gingiva with a mean shrinking tendency of 14 % could be detected. Histological analysis of the biopsies revealed a well integrated collagen22 matrix covered with epithelium. Within the compact layer, mononuclear cells were observed only, while the spongious layer was infiltrated with a cell-rich connective tissue. CONCLUSION: Within its limits, the presented study revealed that the investigated collagen matrix is suitable to enlarge the peri-implant attached gingiva in head and neck cancer patients without adverse reactions or a multinucleated giant cell-triggered tissue reaction. CLINICAL RELEVANCE: The application of the investigated three-dimensional collagen matrix in vestibuloplasty achieved a sufficient amount of peri-implant attached gingiva in head and neck cancer patients. The favorable tissue reaction and the low shrinking tendency make the collagen matrix a promising alternative to autologous tissue grafts.