Purpose: This study was performed to evaluate the effects of flap design, grafting material, and graft dimension on flap tension and the initial volume increase achieved in soft tissue augmentation. Methods: Six fresh porcine jaw cadavers were used in this study. Each side of the jaw was randomly assigned to receive either a standard split-thickness flap or a split-thickness flap with a palatal island. Following flap preparation, random allocation was employed to determine the order of 4 treatment modalities: 3 mm of a volume-stable collagen matrix (VCMX), 6 mm VCMX, 3 mm of a subepithelial connective tissue graft (SCTG), and 6 mm SCTG. Flap tension was measured and the wound was closed after the insertion of each specimen. Intraoral scans were taken before flap preparation and after closure to facilitate profilometric analysis. Results: The palatal island flap exhibited significantly greater overall (P=0.010) and crestal (P=0.007) volume gains compared to the split-thickness flap, regardless of the use of VCMX or SCTG. The palatal island flap was associated with significantly lower flap tension force values (0.6 N; P=0.035) than the split-thickness flap. Both materials (VCMX and SCTG) demonstrated comparable volume gains. Conclusions The findings of this cadaveric study indicate that the use of a palatal island flap effectively reduces flap tension. While both materials (VCMX and SCTG) yielded similar increases in volume, the palatal island flap demonstrated greater volume gains than the splitthickness flap for each grafting material.

Purpose: The aim of this study was to compare changes in soft and hard tissue and the histologic composition following early implant placement in sites with alveolar ridge preservation or spontaneous healing (SH), as well as implant performance up to 1 year after crown insertion. Methods: Thirty-five patients with either intact buccal bone plates or dehiscence of up to 50% following single-tooth extraction of incisors, canines, or premolars were included in the study. They were randomly assigned to undergo one of three procedures: deproteinized bovine bone mineral with 10% collagen (DBBM-C) covered by a collagen matrix (DBBM-C/ CM), DBBM-C alone, or SH. At 8 weeks, implant placement was carried out, and cone-beam computed tomography scans and impressions were obtained for profilometric analysis.Patients were followed up after the final crown insertion and again at 1 year post-procedure. Results: Within the first 8 weeks following tooth extraction, the median height of the buccal soft tissue contour changed by −2.11 mm for the DBBM-C/CM group, −1.62 mm for the DBBM-C group, and −1.93 mm for the SH group. The corresponding height of the buccal mineralized tissue changed by −0.27 mm for the DBBM-C/CM group, −2.73 mm for the DBBM-C group, and −1.48 mm for the SH group. The median contour changes between crown insertion and 1 year were −0.19 mm in the DBBM-C/CM group, −0.09 mm in the DBBM-C group, and −0.29 mm in the SH group. Conclusions Major vertical and horizontal ridge contour changes occurred, irrespective of the treatment modality, up to 8 weeks following tooth extraction. The DBBM-C/CM preserved more mineralized tissue throughout this period, despite a substantial reduction in the overall contour. All 3 protocols led to stable tissues for up to 1 year.

Purpose: The purpose of this study was to examine the local tissue reactions associated with 3 different poly(lactic-co-glycolic acid) (PLGA) prototype membranes and to compare them to the reactions associated with commercially available resorbable membranes in rats. Methods: Seven different membranes—3 synthetic PLGA prototypes (T1, T2, and T3) and 4 commercially available membranes (a PLGA membrane, a poly[lactic acid] membrane, a native collagen membrane, and a cross-linked collagen membrane)—were randomly inserted into 6 unconnected subcutaneous pouches in the backs of 42 rats. The animals were sacrificed at 4, 13, and 26 weeks. Descriptive histologic and histomorphometric assessments were performed to evaluate membrane degradation, visibility, tissue integration, tissue ingrowth, neovascularization, encapsulation, and inflammation. Means and standard deviations were calculated. Results: The histological analysis revealed complete integration and tissue ingrowth of PLGA prototype T1 at 26 weeks. In contrast, the T2 and T3 prototypes displayed slight to moderate integration and tissue ingrowth regardless of time point. The degradation patterns of the 3 synthetic prototypes were similar at 4 and 13 weeks, but differed at 26 weeks. T1 showed marked degradation at 26 weeks, whereas T2 and T3 displayed moderate degradation.Inflammatory cells were present in all 3 prototype membranes at all time points, and these membranes did not meaningfully differ from commercially available membranes with regard to the extent of inflammatory cell infiltration. Conclusions The 3 PLGA prototypes, particularly T1, induced favorable tissue integration, exhibited a similar degradation rate to native collagen membranes, and elicited a similar inflammatory response to commercially available non–cross-linked resorbable membranes.The intensity of inflammation associated with degradable dental membranes appears to relate to their degradation kinetics, irrespective of their material composition.

PURPOSE: To evaluate the effects of intra-alveolar socket grafting, subepithelial connective tissue grafts, and individualized abutments on peri-implant hard and soft tissue outcomes following immediate implant placement. METHODS: This randomized experimental study employed 5 mongrel dogs, with 4 sites per dog (total of 20 sites). The mesial roots of P3 and P4 were extracted in each hemimandible and immediate dental implants were placed. Each site was randomly assigned to 1 of 4 different treatment groups: standardized healing abutment (control group), alloplastic bone substitute material (BSS) + standardized healing abutment (SA group), BSS + individualized healing abutment (IA group), and BSS + individualized healing abutment + a subepithelial connective tissue graft (IAG group). Clinical, histological, and profilometric analyses were performed. The intergroup differences were calculated using the Bonferroni test, setting statistical significance at P<0.05. RESULTS: Clinically, the control and SA groups demonstrated a coronal shift in the buccal height of the mucosa (0.88±0.48 mm and 0.37±1.1 mm, respectively). The IA and IAG groups exhibited an apical shift of the mucosa (−0.7±1.15 mm and −1.1±0.96 mm, respectively). Histologically, the SA and control groups demonstrated marginal mucosa heights of 4.1±0.28 mm and 4.0±0.53 mm relative to the implant shoulder, respectively. The IA and IAG groups, in contrast, only showed a height of 2.6 mm. In addition, the height of the mucosa in relation to the most coronal buccal bone crest or bone substitute particles was not significantly different among the groups. Volumetrically, the IA group (−0.73±0.46 mm) lost less volume on the buccal side than the control (−0.93±0.44 mm), SA (−0.97±0.73 mm), and IAG (−0.88±0.45 mm) groups. CONCLUSIONS: The control group demonstrated the most favorable change of height of the margo mucosae and the largest dimensions of the peri-implant soft tissues. However, the addition of a bone substitute material and an individualized healing abutment resulted in slightly better preservation of the peri-implant soft tissue contour.
Animals ; Bone Substitutes ; Connective Tissue ; Dental Implants ; Dogs ; Mucous Membrane ; Shoulder ; Tissue Transplantation ; Transplants