A strip free gingival graft and a xenogeneic collagen matrix to increase keratinized tissue after vertical bone augmentation.

PURPOSE: After vertical bone augmentation (VBA) surgery, loss of both keratinized tissue (KT) and vestibule depth (VD) take place. This article evaluated KT gain, patient satisfaction, and aesthetic outcomes after a modified apically repositioned flap (ARF) in combination with a strip-free gingival graft (FGG) harvested from the palate and a xenogeneic collagen matrix (XCM) to correct mucogingival distortion (MGD) after VBA. This technique minimizes patient morbidity by reducing the need for extensive masticatory mucosa grafts. MATERIALS: The study included 12 patients with ≤3 mm KT after vertical augmentation procedures. KT gain and tissue thickness were measured. Patient morbidity and aesthetic outcomes were also evaluated. RESULTS: Twenty-four months after surgery, significant VD gain was observed, obtaining a vertical KT augmentation of 5.38 ± 2.06 mm, although tissue thickness increase was only 0.42 ± 0.42mm. Regarding patient satisfaction, aesthetic results evaluating tissue color and texture were satisfactory; the pain was slight, obtaining a score of 2.10 ± 1.13 out of 10, measured using a Visual Analogue Scale (VAS). CONCLUSION: The present retrospective case series study shows that using an apically repositioned flap combined with a strip FGG and an XCM might offer a valid means of achieving KT gain.

Mandibular third molar extraction: perceived surgical difficulty in relation to professional training.

BACKGROUND: Establishing the level of surgical difficulty pre-operatively is an essential step in ensuring correct treatment planning. This study set out to determine whether the knowledge and experience acquired by dentists who had received different levels of training influenced, firstly, the perceived levels of difficulty of a variety of cases of mandibular third molar (MTM) extraction and, secondly, the perceived difficulty deriving from a series of factors (patient-related factors, anatomical and radiographic factors, operative factors). METHODS: This cross-sectional, descriptive, observational study took the form of a survey. Using a visual analog scale (VAS), participants evaluated both the perceived difficulty of 30 cases of MTM extraction described by means of digital panoramic radiographs and the perceived difficulty deriving from a series of factors conditioning MTM extraction. The results underwent statistical analysis with SPSS Statistics 28.0 software. Non-parametric tests (Mann Whitney test for independent samples and the Kruskal-Wallis test) were applied. RESULTS: A total of 389 surveys were available for analysis. Dental practioners with no surgical training saw the intervention as presenting greater difficulty. Professionals with postgraduate training in oral surgery considered patient-related factors more important than operative factors, in contrast to dentists who had not received oral surgery training. CONCLUSIONS: Dental training has a signficant influence on the perceived difficulty of MTM extraction and also affects opinions about which factors have greater or lesser influence on surgical difficulty.

Influence of CAD/CAM scanning method and tooth-preparation design on the vertical misfit of zirconia crown copings.

PURPOSE: To evaluate the influence of scanning method, finish line type and occlusal convergence angle of the teeth preparations on the vertical misfit of zirconia crown copings. METHODS: 20 standardized stainless-steel master dies were machined simulating full-crown preparations. The total convergence angle was 15 degrees or 20 degrees (n=10 each). Two of the finish line types: a chamfer (CH) and a shoulder (SH) were prepared around the contour of each abutment. Over these dies, 20 structures were made by CAD/CAM (Cercon, Dentsply). An optical laser digitized the wax patterns of 10 single-unit copings (WS), and 10 abutments were direct-scanned to design the cores by computer (DS). Zirconia milled caps were luted onto the models under constant seating pressure. Vertical discrepancy was assessed by SEM. Misfit data were analyzed using ANOVA and Student-Newman-Keuls (SNK) test for multiple comparisons at alpha = 0.05. RESULTS: Vertical gap measurements of WS copings were significantly higher than those of DS frames (P < 0.0001). SH exhibited statistically higher discrepancies than CH when combined with a 15-degree occlusal convergence angle regardless of the scanning method (P < 0.05). The taper angle of the preparation (15 degrees vs. 20 degrees) had no effect on the marginal adaptation of chamfered samples.

Influence of CAM vs. CAD/CAM scanning methods and finish line of tooth preparation in the vertical misfit of zirconia bridge structures.

PURPOSE: To evaluate the influence of CAD/CAM scanning method (wax-up digitization vs. direct scanning of tooth preparation) and finish line type (chamfer vs. shoulder) on the vertical fit of zirconia frameworks for three-unit posterior-lower bridges. METHODS: 30 sets of two stainless steel master dies were prepared with different marginal designs (chamfer and shoulder) around the contour of each abutment. Over these samples, 30 structures for three-unit posterior-lower bridges were made with Cercon Smart Ceramics CAD/CAM system (Dentsply). An optical laser digitized the wax patterns of 15 bridge structures, and 15 pairs of master dies were directly scanned for designing by computer the remaining half of frames. All zirconia milled structures were luted onto the metallic models with a special clamp made-up to maintain constant seating pressure. Vertical discrepancy around the margins was assessed under scanning electron microscopy (SEM). Misfit data was analyzed using two-way ANOVA and Tukey's test for multiple comparisons at a = 0.05. RESULTS: Vertical discrepancy of the wax-up/digitized bridge structures was significantly higher than that of the computer-designed frameworks (P < 0.0001). No statistically significant differences were found between the chamfer and shoulder vertical misfit values assessed around the metallic models margins (P = 0.55).