Clinical evaluation of two-piece zirconia abutments with bonded titanium inserts for implant-supported restorations.

STATEMENT OF PROBLEM: Information about the long-term evaluation of 2-piece zirconia abutments (TPZAs) with bonded titanium inserts for implant-supported restorations is sparse. PURPOSE: The purpose of this clinical study was to evaluate the clinical outcome of TPZAs with bonded titanium inserts for implant-supported restorations. MATERIAL AND METHODS: This study retrospectively evaluated the records of patients who received implant restorations supported by TPZAs with bonded titanium inserts. The patients were recalled between January 2017 and December 2017 so that the restorations could be examined clinically and radiographically for technical and biological complications. RESULTS: A total of 27 patients with 30 restorations and 42 zirconia abutments (ZAs) were included in the study. The patient records revealed that all implants remained integrated. However, 5 restorations supported by seven ZAs in 4 patients had to be refabricated because of abutment failure before the recall. Six of the failed abutments were in the molar area, with a combination of zirconia and titanium as the connection platform. Additional complications included screw loosening (1 patient), ceramic chipping (1 patient), and peri-implantitis (1 patient). The mean observation period was 6.6 ±1.5 years (range: 3.6 to 9.2 years). CONCLUSIONS: After a mean observation period of 6 years after insertion, TPZAs with bonded titanium inserts appear to be a suitable treatment option in the anterior and premolar regions. However, in the molar area, the use of the same type of ZA without a complete metal-to-metal connection platform to support the restoration led to a high incidence of fracture.

Retrospective and Clinical Evaluation of Aftermarket CAD/CAM Titanium Abutments Supporting Posterior Splinted Prostheses and Single Crowns.

PURPOSE: To evaluate the clinical outcomes of aftermarket computer-aided design/computer-assisted manufacturing (CAD/CAM) titanium abutments supporting splinted prostheses and single crowns in the posterior region. MATERIALS AND METHODS: This study retrospectively evaluated the records of patients who received posterior implant-supported splinted restorations and single crowns supported by aftermarket CAD/CAM titanium abutments. Recall and clinical examination of the patients were performed between January 2017 and February 2018. A logistic regression was conducted to evaluate the influence of variables on the occurrence of complications and success rates. Correlations between the bone-level change and variables were calculated using the Spearman correlation. RESULTS: One hundred thirty-five patients with 287 implants (86 crowns and 97 splinted prostheses) were recalled and examined clinically and radiographically after a mean observation period of 6.3 ± 1.2 years (range 4.1 to 9 years). Failure of 3 implants led to a survival rate of 99.0%. Complications included 18 (9.8%) ceramic chippings, 15 (8.2%) screw loosenings, 8 (4.4%) decementations, 52 (38.5%) patients with peri-implant mucositis, and 9 (6.7%) patients with peri-implantitis. A significantly higher incidence of ceramic chipping occurred with bruxers (odds ratio [OR] = 3.939, 95% confidence interval [CI] = 1.28-12.09, P < .05). All screw loosenings occurred in single crowns. All decementations were observed in restorations cemented with temporary cement. Marginal bone loss around implants was significantly correlated with smoking (r = -0.155, P < .05). Hypertension was significantly associated with peri-implant mucositis (OR = 4.7, 95% CI = 1.65-13.39, P < .05). The technical success rate was 80.1%. The biologic success rate was 57%. There was no association between the restoration type and the success rates of the restorations. CONCLUSIONS: Using aftermarket CAD/CAM titanium abutments to support posterior restorations yielded comparable survival and success rates after a mean observation period of 6 years. However, in light of the relatively high incidence of screw loosenings, especially in patients receiving single-implant crowns, informing patients of the additional chairside aftercare with this type of treatment option is recommended.

Compatible CAD-CAM titanium abutments for posterior single-implant tooth replacement: A retrospective case series.

STATEMENT OF PROBLEM: In addition to the original abutments provided by implant companies, compatible computer-aided design and computer-aided manufacturing (CAD-CAM) abutments are also available from different manufacturers. However, the combination of abutments and implant systems from different manufacturers may lead to mechanical problems between components. Little has been reported on the clinical performance of this treatment option. PURPOSE: The purpose of this retrospective case series was to evaluate the outcome of compatible CAD-CAM titanium abutments (TiAs) for posterior single-implant tooth replacement (PSITR) up to 6 years after insertion. MATERIAL AND METHODS: Eighty-one patients (34 men, 47 women) who received PSITR restored with compatible CAD-CAM TiAs and had a final recall examination between May 2014 and April 2015 were included in this study. Clinical and radiographic examinations were documented. Retrospective evaluation of the patient records was also performed. Correlations between bone-level changes and variables were calculated using the Spearman correlation. RESULTS: Implant and prosthesis survival rates were 100%. Twenty technical complications were observed, including 9 decementations of the crown, 6 screw loosenings, and 5 ceramic fractures. Periimplant mucositis was diagnosed in 36 patients (44.4%) and periimplantitis in 6 patients (7.4%). Correlation analysis showed a significant effect of the extent of periodontal bone loss of the remaining teeth on the marginal bone-level changes around implants (r=0.548, P<.001). CONCLUSIONS: Compatible CAD-CAM TiAs provide a viable treatment option for PSITR. However, in light of relatively high screw-loosening and decementation rates, choosing appropriate cements and abutment manufacturers is essential to improve the clinical performance of this treatment option.

A gingival cul-de-sac following a root coverage procedure with a subepithelial connective tissue submerged graft.

BACKGROUND: The subepithelial connective tissue graft (SCTG) used as a submerged graft in combination with a partial thickness advanced flap or rotated flap is a predictable technique for achieving coverage of the denuded root surface and/or for increasing the width of attached gingiva in Miller's class I and II marginal tissue recessions. However, even with a successful result, complications may occasionally occur. METHODS: A 4-mm marginal tissue recession with an insufficient zone of attached gingiva on the facial aspect of a mandibular left lateral incisor (#23) was covered with a submerged SCTG and an envelope partial thickness flap. The mucogingival defect was successfully corrected. Nevertheless, the facial gingiva, specifically between teeth #22 (mandibular left canine) and #23, remained bulky and was reshaped 6 months postoperatively. A 5-mm long gingival cul-de-sac with an intermittent thick white discharge was detected 3 months following the gingivoplasty procedure. RESULTS: With a periodontal probe kept in the tract, the lining of the cul-de-sac was exposed to the oral cavity by making an incision on the facial gingiva, along the axis of the probe, through to the lumen. The gingival tissue was then removed with a rotary bur until only a thin layer of periosteum remained. The mucosal defect was subsequently repaired by grafting with a non-submerged SCTG. The gingival contour was significantly improved and no sign of recurrence was noted up to 4 years later. CONCLUSIONS: The existence of a cyst cannot be verified without a histological evaluation. However, the development of a gingival cyst should be suspected with persistent tissue bulkiness and/or emergence of a thick white discharge from a site where a submerged SCTG procedure was performed. In addition, the ill-circumscribed border around the lesion makes complete elimination of the pathosis relatively hard to achieve by a "superficial" gingivoplasty procedure.

Acellular dermal matrix allografts to achieve increased attached gingiva. Part 2. A histological comparative study.

BACKGROUND: In part 1 of this study, we compared the clinical efficacy of freeze-dried acellular dermal matrix (ADM) allograft in 6 patients with autogenous free gingival graft (FGG) in 6 patients for increasing the width of attached gingiva in the mandibular anterior area. The purpose of the present study was to histologically compare the microstructure of ADM and FGG treated sites from the same group. METHODS: Biopsies were harvested from all 12 patients at 6 months postsurgery. The biopsies included the grafted sites with adjacent alveolar mucosa and gingiva propria and also donor palatal mucosa saved at the time of surgery. The 5 microm thick, neutral buffered formalin fixed, paraffin-embedded tissue sections were stained with hematoxylin and eosin (H&E), Masson's trichrome, and Verhoeff-van Gieson stains in order to investigate the density of collagen and elastic fibers. Additional sections were stained with periodic acid-Schiff (PAS) and Papanicolaou's stain to identify the presence of glycogen granules in the epithelial layer and to highlight the keratin layer respectively. RESULTS: The unique appearance of ADM-derived tissue did not parallel any known oral mucosa. The connective tissue portion contained dense to extremely dense collagen fibers along with scattered elastic fibers. The demarcations between the ADM graft and the coronal gingiva as well as the apical alveolar mucosa were usually not very defined. A moderate to thin epithelial layer, with heterogeneous expression of keratinization and flat epithelium-connective tissue interface, covered the lamina propria. Both the thickness of the epithelium and the degree of keratinization decreased in apical direction, being mostly para- or orthokeratinized in the area close to gingiva and non-keratinized adjacent to the alveolar mucosa. In the FGG-treated sites, the density of collagen fibers was less than in ADM-derived tissue, palatal mucosa, and gingiva. Elastic fibers were very sparse, comparable to gingiva, but much less than in ADM-derived tissue. The epithelium was moderate, somewhat thinner but the shape of the rete ridges resembled that of palatal mucosa. Similar to gingiva epithelium, the epithelium of the FGG-treated area was relatively uniform in both thickness and keratinization, mostly para-keratinized with a well defined border to the non-keratinized alveolar mucosa. Underneath the FGG-alveolar mucosa junction, a scar band composed of extremely dense collagen fibers consistently existed. CONCLUSIONS: The results of this 6-month histological evaluation suggest that: 1) the resultant tissue types of ADM grafts were similar to "scar" tissue; 2) the non-vital dermal matrix of ADM allograft lacked the capability of directing cyto-differentiation of the covering epithelium; 3) autogenous FGG-derived tissue was neither identical to donor palatal mucosa nor to adjacent gingiva propria; 4) the connective tissue of donor palatal mucosa only partially contributed to the differentiation of the epithelium covering the FGG-treated area; and 5) the epithelium/connective tissue microenvironment surrounding the recipient site influenced the epithelial differentiation of the graft; this may play a more critical role in ADM grafting than in the grafting of autogenous FGG.