Digital three-dimensional assessment of free gingival graft remodeling over 12 months.

OBJECTIVE: To digitally evaluate the three-dimensional (3D) remodelling of FGG used to treat RT2 gingival recessions and lack of keratinized tissue on mandibular incisor teeth. METHODS: Data from 45 patients included in a previous multicentric RCT were analyzed. Silicone impressions were taken before (baseline) and 3, 6 and 12 months after standardized FGG placement. Casts were scanned and images were superimposed, using digital software, to obtain measurements of estimated soft tissue thickness (eTT; 1, 3, and 5 mm apical to baseline gingival margin). In addition, soft tissue volume (STV) and creeping attachment (CA) were assessed. RESULTS: All patients exhibited postoperative eTT and STV increases, at all time points. The greatest mean thickness gain was observed at eTT3 (1.0 ± 0.4 mm) at 12 months. At 12 months, STV was 52.3 ± 21.1 mm3, without relevant changes compared to the 3- and 6-month follow-up. CA, which was observed as early as six months postoperatively, was evident in ∼85 % of teeth at 12 months. CONCLUSIONS: Application of FGG was an effective phenotype modification therapy, as shown by the significantly increased tissue thickness postoperatively. Despite the use of FGG technique not aiming for root coverage, digital 3D assessment documented the early and frequent postoperative occurrence of CA, which helped improve recession treatment outcomes. CLINICAL SIGNIFICANCE: The use of 3D assessment methodology allows precise identification of the tissue gain obtained with FGG, which, regardless of technique, results in predictable phenotype modification and frequent occurrence of creeping attachment.

Contour changes of peri-implant tissues are minimal and similar for a one- and a two-piece implant system over 12 years.

OBJECTIVES: To assess contour changes of peri-implant tissues comparing a one- and a two-piece dental implant system over 12 years. MATERIALS AND METHODS: Patients seeking implant therapy were enrolled and randomly allocated to receive implants (a one-piece (STM) or a two-piece (BRA) system). Impressions were taken at the time of insertion of the final reconstruction (BL), after 1 year (FU-1), 5 years (FU-5), and at 12 years (FU-12). Thirty patients were included in the analysis (STM, 16; BRA, 14). Digital scans of casts were superimposed and analyzed in an image analysis program. Measurements included changes of the crown height, contour changes on the buccal side of the implants and the contralateral teeth (control). RESULTS: Contour changes at implant sites revealed a loss of - 0.29 mm (STM) and - 0.46 mm (BRA) during an observation period of 12 years. Contour changes at the corresponding tooth sites amounted to - 0.06 mm (STM) and - 0.12 mm (BRA) during the same time period. The implant crown gained 0.25 mm (STM) and 0.08 mm (BRA) in height due to recession of the marginal mucosa. The corresponding gain in crown height at the contralateral tooth sites amounted to 0.36 mm (STM) and 0.10 mm (BRA). Interproximal marginal bone level changes measured - 0.28 mm (STM) and - 1.11 mm (BRA). The mean BOP amounted to 38.8% (STM) and 48.7% (BRA) at the 12-year follow-up (FU-12). CONCLUSION: Minimal changes of the peri-implant soft tissue contour were observed at implant sites over the period of 12 years irrespective of the use of a one- or a two-piece implant system. The differences between the implant sites and corresponding teeth were clinically negligible. CLINICAL RELEVANCE: Peri-implant soft tissue stability is of high clinical relevance when monitoring dental implant sites on the long run. Clinical data on the extent of soft tissue changes around different implant systems are scarce. The present RCTs demonstrate minimal changes of the peri-implant soft tissue contour 12 years after implant insertion independent of the use of a one- or a two-piece implant system.

The positive effect of tenting screws for primary horizontal guided bone regeneration: A retrospective study based on cone-beam computed tomography data.

OBJECTIVES: To radiographically evaluate the effect of the adjunctive use of tenting screws (TS) for primary horizontal guided bone regeneration (GBR). MATERIALS & METHODS: Twenty-eight patients in need of staged bone augmentation were consecutively treated in a private practice. A xenogenic particulate bone substitute material (DBBM) and a resorbable collagen membrane were used in all patients. Subjects were divided into two groups: control (conventional GBR; n = 22) and test (tenting screws in conjunction with GBR - TS; n = 22). CBCT images were obtained before augmentation and after 6-8 months. CBCTs were superimposed, and linear horizontal measurements were performed. Alveolar ridge width (RW) and ridge width change (RWchange) were assessed at 1, 3, 5, and 7 mm below the bone crest. RESULTS: Forty-four sites in 28 patients were evaluated. No differences between the groups were detected for RW at baseline (TS: 5.87 ± 2.41; control: 5.36 ± 1.65). Regarding RWchange, TS promoted an additional effect at 1 and 3 mm below the crest compared to control (p < .05; RWchange-1 TS: 3.72 ± 2.46; control: 1.25 ± 3.05; RWchange-3 TS: 3.98 ± 2.53; control: 2.50 ± 2.02). The final RW was greater in group TS compared to the control group at the 1, 3, and 5 mm level (p < .05). CONCLUSIONS: The use of tenting screws exerted a positive effect on staged GBR with a greater final RW at the 3 mm level. In addition, GBR in conjunction with TS was able to provide consistent bone augmentation at lingual/palatal sites.

Deproteinized bovine bone mineral is non-inferior to deproteinized bovine bone mineral with 10% collagen in maintaining the soft tissue contour post-extraction: A randomized trial.

OBJECTIVES: To test the non-inferiority of demineralized bovine bone mineral (DBBM) compared to demineralized bovine bone mineral with 10% collagen (DBBM-C) for the maintenance of the soft tissue contour after tooth extraction in the esthetic zone. MATERIAL AND METHODS: Sixty-five patients randomly received ridge preservation at a single site in the anterior maxilla with DBBM or DBBM-C. Both, DBBM and DBBM-C, were covered with a collagen matrix. Profilometric analyses were performed at baseline (BL), immediately after treatment (PO), and at 4 months (FU; day of implant placement). The main outcome was the horizontal mean change (HC) at the buccal aspect. The measurements also included changes of the estimated soft tissue thickness (eTT) at 1, 3, and 5 mm below the buccal gingival margin. Descriptive analysis was performed, and differences between groups were analyzed using independent samples t test. The non-inferiority test was performed for HC. RESULTS: At 4 months, the horizontal mean change (HC) was -1.43 mm (±0.53 mm) (DBBM-C) and -1.32 mm (±0.53 mm) (DBBM). Change of the estimated soft tissue thickness (eTT) between baseline (BL) and four months of follow-up (FU) at 1, 3, and 5 mm amounted to -4.58 mm (±2.02 mm), -2.40 mm (±0.97 mm), and -1.37 mm (±0.78 mm) for DBBM-C and to -4.12 mm (±1.80 mm), -2.09 mm (±0.91 mm), and -1.23 mm (±0.72 mm) for DBBM. The differences between the groups were not statistically significantly for any of the outcome measures (p > .05). CONCLUSIONS: DBBM is non-inferior to DBBM-C for the maintenance of the soft tissue contour 4 months after tooth extraction.

Combined use of xenogeneic bone substitute material covered with a native bilayer collagen membrane for alveolar ridge preservation: A randomized controlled clinical trial.

AIM: The aim of this split-mouth randomized controlled study was to evaluate radiographic dimensional changes after tooth extraction in posterior sites treated with a ridge preservation technique or left for spontaneous healing. MATERIALS AND METHODS: In a total of 18 patients, tooth extraction in posterior sites of the upper and lower jaw was performed in a split-mouth design. The post-extraction sockets were randomly assigned to the following two treatment modalities: deproteinized bovine bone mineral (DBBM) with 10% collagen (DBBM-C) covered with a native bilayer collagen membrane (NBCM) (test group) and spontaneous healing (control group). Cone beam computed tomography (CBCT) scans were performed after extractions, 3 and 6 months later. The following parameters were measured: the height of the buccal bone plate (BH), height of the palatal bone plate (PH), horizontal width of the extraction socket at 1 mm, 3 mm, and 5 mm (HW-1, HW-3, HW-5), and the horizontal width (thickness) of the buccal bone plate at 1 mm, 3 mm, and 5 mm (BHP-1, BHP-3, BHP-5). Statistical analysis was performed applying a nonparametric Wilcoxon signed-rank test. RESULTS: The CBCT analysis showed a bone loss compared to baseline in test and control group. The measurements which have reached statistically significant differences at 6 months were BH (test: -2.31% vs control: -13.11%), PH (test: -2.07% vs control: -15.32%), HW-1 (test: -17.14% vs control: -32.47%), and HW-3 (test: -11.65% vs control: -28.47%). CONCLUSIONS: The posterior ridge preservation technique using DBBM-C covered with a NBCM is a valid approach reducing the amount of the radiographic loss in alveolar ridge dimensions.

Volumetric changes and peri-implant health at implant sites with or without soft tissue grafting in the esthetic zone, a retrospective case-control study with a 5-year follow-up.

OBJECTIVES: To evaluate the volumetric changes and peri-implant health at implant sites with and without previous soft tissue grafting over a 5-year observation period. MATERIAL AND METHODS: In 18 partially edentulous patients, dental implants were placed in the esthetic zone (15-25) with simultaneous guided bone regeneration, followed by submerged healing. During the healing phase, eight patients (test) received a subepithelial connective tissue graft, whereas 10 patients (control) did not receive any soft tissue augmentation. Subsequently, abutment connection was performed and final reconstructions were inserted. Impressions were taken 1 week after crown insertion and at 5 years. Obtained casts were scanned and superimposed for volumetric and linear measurements. The mean distance (MD) in the mid-buccal area between the two surfaces and the differences in buccal marginal mucosal level (bMMLchange ) and in ridge width (RWchange ) were evaluated. Peri-implant health was assessed using probing pocket depth (PPD) values, plaque index (PlI) and bleeding on probing (BOP). RESULTS: At a median follow-up time of 60.5 months a median MD of -0.38 mm (Min: -0.94; Max: -0.03) (test) and of -0.51 mm (Min: -0.76; Max: 0.05) (control) was calculated. The level of the margo mucosae (bMMLchange ) demonstrated a median loss of -0.42 mm (Min: -1.1; Max: -0.01) (test) and of -0.33 mm (Min: -1.02; Max: 0.00) (control). The median RWchange ranged between -0.44 mm and -0.73 mm (test) and between -0.49 mm and -0.54 mm (control). Mean PPD values slightly increased, whereas PlI and BOP remained stable over time in both groups. None of the comparisons between the groups revealed statistically significant differences (P > 0.35). A small sample size must be considered, however. CONCLUSIONS: Limited by a retrospective case-control study design, implant sites with and without soft tissue grafting on the buccal side revealed only minimal volumetric and linear changes and stability of peri-implant parameters over 5 years.

Spectrophotometric analysis of fluorescent zirconia abutments compared to "conventional" zirconia abutments: A within subject controlled clinical trial.

BACKGROUND: Zirconia abutments are frequently used for implant-supported single crowns. Even though demonstrating esthetic benefits compared to metal abutments, zirconia abutments lead to an increased brightness of the peri-implant mucosa compared to natural teeth and are not ideal from an esthetic point of view. PURPOSE: To test whether or not a fluorescent hybrid zirconia abutment offers superior esthetics compared to a non-fluorescent one-piece zirconia abutment based on spectrophotometric analysis. MATERIALS AND METHODS: In 24 patients with 24 single-tooth implants, 2 types of reconstructions were fabricated: a directly veneered one-piece zirconia abutment/crown (control) and a directly veneered fluorescent hybrid zirconia abutment/crown (test). Spectrophotometric assessment was performed: prior to abutment insertion (WA), at abutment try-in (A), at the try-in of the final crowns (C). Color differences (ΔE) were assessed compared to the gingiva of natural teeth (T) and between the reconstructions. RESULTS: At abutment try-in, ΔE values were 8.49 ± 3.59 for AControl and 8.27 ± 4.03 for ATest compared to T. At crown insertion, ΔE values were 7.61 ± 4.03 for CControl and 8.32 ± 3.57 for CTest compared to T. The difference in ΔE values between AControl and ATest was 0.23 ± 2.54 (P = .37), whereas the difference in ΔE values between CControl and CTest was -0.66 ±3.45 (P = .48). For all cases with a mucosal thickness ≤2 mm, the comparison between CControl and CTest was significant in favor of the control group (P = .03). CONCLUSIONS: Both types of reconstructions were similar in terms of esthetics. Incases with a mucosal thickness of <2 mm, the soft tissue discoloration compared to the natural gingiva was more pronounced for the fluorescent hybrid zirconia reconstructions.

Recombinant bone morphogenetic protein-2 and platelet-derived growth factor-BB for localized bone regeneration. Histologic and radiographic outcomes of a rabbit study.

OBJECTIVES: Improvement in localized bone regeneration is needed to avoid the use of autogenous tissue. For that purpose, the use biologic mediators was proposed. The aim was to test whether or not one of two biologic mediators, recombinant human bone morphogenetic protein-2 (rhBMP-2) or recombinant platelet-derived growth factor (rhPDGF-BB), is superior to the other and to control groups for localized bone regeneration. MATERIALS AND METHODS: Four cylinders (height: 5 mm; diameter: 7 mm) were screwed on the parietal and frontal bones at the cranium in 12 rabbits. The cylinders either received (i) deproteinized bovine bone mineral (DBBM) mixed rhBMP-2 (DBBM/BMP-2), (ii) DBBM mixed with rhPDGF-BB (DBBM/PDGF), (iii) DBBM (DBBM), and (iv) empty control (control). Rabbits were euthanized at 2 and 8 weeks (n = 6, respectively). Conventional histomorphometric and micro-CT analyses were performed. Parametric linear mixed models were applied for the analyses with Bonferroni correction for the multiple group comparisons. RESULTS: The area of bone regeneration (histology; AAHisto ) at 2 weeks peaked for DBBM (41.91%) with statistically significantly greater values compared to DBBM/PDGF and the control group (P < 0.05). At 8 weeks, mean AAHisto values were 96.29% (DBBM/BMP-2), 46.37% (DBBM/PDFG), 39.66% (DBBM), and 35.98% (control) (DBBM/BMP-2 vs. all groups (P < 0.05)). At 8 weeks, bone regeneration was greatest for DBBM/BMP-2 (35.62%) with statistically significant differences compared to all other groups (P < 0.05). The area of bone regeneration (micro-CT; AAm-CT ) at 2 weeks amounted to 43.87% (DBBM/BMP-2), 42.81% (DBBM/PDFG), 48.71% (DBBM), and 0.96% (control). The control group demonstrated statistically significantly less AAm-CT compared to all groups (P < 0.05). At 8 weeks, mean AAm-CT values were 63.65% (DBBM/BMP-2), 50.21% (DBBM/PDFG), 44.81% (DBBM), and 4.57% (control) (P > 0.05). CONCLUSIONS: The use of rhBMP-2 significantly enhanced bone regeneration compared to all other groups including the group with rhPDGF-BB.

Localized bone regeneration around dental implants using recombinant bone morphogenetic protein-2 and platelet-derived growth factor-BB in the canine.

OBJECTIVES: To test whether or not one of two biological mediators (recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human platelet-derived growth factor (rhPDGF-BB)) is superior to the other and compared with control groups for bone regeneration around implants based on histomorphometrical outcome measures. MATERIALS AND METHODS: Box-type defects (10 × 5 × 5 mm) were prepared on the buccal sides of the left and right edentulous ridge in ten mongrel dogs. Implants were placed at each site, the defects either received (i) bovine-derived particulated bone mineral (DBBM) mixed with rhBMP-2 and a collagen membrane (CM) (DBBM/BMP-2), (ii) DBBM mixed with rhPDGF-BB and CM (DBBM/PDGF), (iii) DBBM and CM (DBBM) and (iv) empty control (control). Animals were euthanized post-surgery at 8 weeks and 16 weeks. Histomorphometrical analyses were performed. RESULTS: The mean percentages of regenerated area within total defect area amounted to 56.95% for DBBM/BMP-2, 48.86% for DBBM/PDFG, 33.44% for DBBM and 1.59% for control at 8 weeks, and 26.79% for DBBM/BMP-2, 23.78% for DBBM/PDFG, 30.21% for DBBM and 5.07% for control at 16 weeks with no statistically significant differences between the groups (P > 0.05). The mean amount of regenerated bone was 26.97% for DBBM/BMP-2, 22.02% for DBBM/PDFG, 5.03% for DBBM and 1.25% for control at 8 weeks, and at 16 weeks, these values were lower in the two groups with biological mediators (DBBM/BMP-2 = 13.35%; DBBM/PDGF = 6.96%) and only slightly increased in group DBBM (10.68%) and the control group (4.95%) compared with 8 weeks. The first bone-to-implant contact values on the buccal side were minimal for DBBM/BMP-2 (0.57 mm) and maximal for control (3.72 mm) at 8 weeks. CONCLUSIONS: The use of biological mediators (rhBMP-2 and rhPDGF-BB) can increase the amount of bone regeneration at dehiscence-type defects compared with controls at 8 weeks, but not at 16 weeks due to enhanced hard tissue remodeling processes.

Evaluation of the effects of periodontal treatment on levels of ascorbic acid in smokers.

Smokers consistently have lower levels of vitamin C, which is important for optimal healing, especially following invasive procedures. Some studies demonstrated that patients undergoing surgery experience significant reductions in systemic vitamin C levels, presumably due to higher metabolic utilization of existing vitamin pools. However, there appear to be no studies evaluating the effect of non-surgical periodontal therapy on plasma levels of vitamin C. The aim of this study was to evaluate if non-surgical periodontal therapy is able to reduce the plasmatic level of ascorbic acid (AA) in smokers. Twenty-six systemically healthy adult (> 40 years) smokers (10 cigarettes/day for > 5 years) who needed scaling and root planing (SRP) for chronic periodontitis were recruited. The sessions of SRP (per quadrant) were scheduled 7 days apart from each other. Blood was collected by venipuncture before the first session of SRP and at the end of the periodontal treatment. The ascorbate concentrations in plasma were assessed according to a published protocol. A paired t-test (p < 0.05) evaluated the statistical significance of differences between the mean values obtained pre- and post-treatment. In general, there was no significant change in levels of AA; however, in 38% of patients, increased levels of AA in plasma were observed after SRP. In 15% of the patients, no change was noted, while 47% of patients showed a reduction in levels of AA after SRP. It can be concluded that although almost half of individuals presented with reduced levels of ascorbic acid after treatment, SRP did not significantly change the levels of AA in smokers.