Peri-implant Bone Loss of Tissue-Level and Bone-Level Implants in the Esthetic Zone with Gingival Biotype Analysis.

PURPOSE: The esthetic outcome of dental implants can be compromised when some degree of bone loss occurs around the implant. This may particularly affect the tissue-level (TL) design. Therefore, bone-level (BL) design implants may be preferable if a natural emergence profile is important. Notwithstanding the implant design, the gingival biotype has been identified as a crucial factor in the stability of crestal bone. The objective of this study was to investigate bone loss in patients with different gingival biotypes at TL and BL implant sites in the esthetic zone. MATERIALS AND METHODS: In 41 patients, 20 TL and 22 BL implant procedures were carried out. Intraoral radiographs of all of the 42 sites were taken immediately after implant insertion as well as during the follow-up examination. The analysis of bone height was conducted using a computerized technique. The TRAN method was used to determine the gingival biotype. RESULTS: After a mean in situ period of 4.9 years in the TL group, 12 implants with a thick biotype had a mean bone loss of 0.21 mm (SD: 0.43 mm). The eight implants with a thin biotype had a loss of 0.05 mm (SD: 0.47 mm; P = .31). After a mean in situ period of 1.9 years, the 14 BL sites with a thick biotype showed a mean bone change of -0.03 mm (SD: 0.38 mm). In the eight implants with a thin biotype, a change of +0.09 mm (SD: 0.32 mm; P = .84) was noted. CONCLUSION: Analysis of the obtained results did not reveal a dependency of bone height on implant design or on gingival biotype. However, prior to choosing an implant design, it may nevertheless be beneficial to screen for transparent soft tissues, where the BL design offers a more natural emergence profile. For this purpose, the TRAN method is clearly the fastest and easiest.

Long-Term Esthetic Outcome of Tissue-Level and Bone-Level Implants in the Anterior Maxilla.

PURPOSE: The aim of this study was to assess and compare the esthetic outcome of tissue-level (TL) and bone-level (BL) implants that had been placed as single implants in the anterior maxilla. MATERIALS AND METHODS: Between 2001 and 2008, patients were treated using TL implants (Straumann). From 2008 until 2012, patients received the newly developed BL implant (Straumann). All patients with a single anterior maxillary implant who came to check-ups regularly were contacted and invited to take part in the study. Standardized photographs were taken to conduct the evaluation. Five observers analyzed the esthetic outcome using the pink esthetic score (PES). For the purpose of statistical analysis, the Wilcoxon rank sum test was applied. Interobserver reliability was evaluated with Krippendorff's alpha. RESULTS: Forty-six patients agreed to take part in the study. The study comprised 10 immediate (TL = 6, BL = 4), 21 early (TL = 6, BL = 15), and 15 delayed implantations (TL = 11, BL = 4). All implant sites were simultaneously augmented. The prosthetic restorations were delivered 6 to 24 weeks after implant placement in the TL group and 10 to 14 weeks after implant placement in the BL group. Esthetic evaluation was performed after a mean period of 9.5 years for TL implants (range: 5.5 to 12.0) and 3.7 years for BL implants (range: 2.6 to 7.1). The overall PES was 8.49 (SD: 2.35) for TL implants and 9.29 (SD: 1.90) for BL implants (P = .37). Comparison of single parameters was between P = .24 and P = .83, indicating no statistically significant difference between the two implant types. CONCLUSION: Within the limits of this study, it can be stated that both implant designs showed comparably satisfying esthetic results.

Alveolar Ridge Dimension 6 Months After Implant Placement with Simultaneous Hard Tissue Augmentation.

PURPOSE: When failing front teeth are replaced by implants, vestibular bone deficiencies frequently require augmentation, even though the amount of missing alveolar volume may vary. The objective of this study was to analyze the horizontal alveolar ridge dimension after implant placement and simultaneous augmentation, and to compare it to the condition at the contralateral natural site. MATERIALS AND METHODS: Forty-eight patients with a failing maxillary incisor received an immediate or early implant (Straumann Bone Level), according to a randomized study protocol. The vestibular wall of the implant site was reconstructed and moderately overcontoured with bovine hydroxyapatite and a collagen membrane (BioOss, BioGide, Geistlich). Provisional restoration followed either immediately, or after a 6-week healing period. To investigate the vestibular volume 6 months after surgery, a plaster model of the maxilla was scanned with cone beam computed tomography (CBCT; Morita 3D) and evaluated using coDiagnostiX software (Dental Wings). Statistical analysis comprised one- and two-sample t tests. RESULTS: The ridge volume was not significantly influenced by the treatment schedule. The vestibular segments had a mean ± SD volume of 207.9 ± 102.5 mm³ for the implant sites, and 202.1 ± 101.5 mm³ for the corresponding natural sites (P = .28). The difference in vestibular volume between implant sites and natural tooth sites was 10.4 ± 36.2 mm³ for immediate implantation, and 0.00 ± 31.1 mm³ for early implantation (P = .32). Comparing immediate and early restoration, a difference of 0.4 mm³ and 12.5 mm³ between the implant and contralateral site was found (P = .23). CONCLUSION: Six months after treatment, no significant differences between the alveolar volumes at augmented implant sites and natural sites were found. Moderate buccal overcontouring may have been beneficial to achieve a symmetrical contour. Long-term follow-up investigation will document if the restored volume remains stable over time.

Accuracy of impression scanning compared with stone casts of implant impressions.

STATEMENT OF PROBLEM: Accurate virtual implant models are a necessity for the fabrication of precisely fitting superstructures. PURPOSE: The purpose of this in vitro study was to evaluate different methods with which to build an accurate virtual model of a 3-dimensional implant in the oral cavity; this model would then be used for iterative computer-aided design and computer-aided manufacturing (CAD-CAM) procedures. MATERIAL AND METHODS: A titanium master model with 3 rigidly connected implants was manufactured and digitized with a noncontact industrial scanner to obtain a virtual master model. Impressions of the master model with the implant position locators (IPL) were made using vinyl siloxanether material. The impressions were scanned (Impression scanning technique group). For the transfer technique and pick-up technique groups (each group n=20), implant analogs were inserted into the impression copings, impressions were made using polyether, and casts were poured in Type 4 gypsum. The IPLs were screwed into the analogs and scanned. To compare the virtual master model with each virtual test model, a CAD interactive software, ATOS professional, was applied. The Kruskal-Wallis test was subsequently used to determine the overall difference between groups, with the Mann-Whitney U test used for pairwise comparisons. Through Bonferroni correction, the α-level was set to .017. RESULTS: The outcome revealed a significant difference among the 3 groups (P<.01) in terms of accuracy. With regard to total deviation, for all axes, the transfer technique generated the greatest divergence, 0.078 mm (±0.022), compared with the master model. Deviation with the pick-up technique was 0.041 mm (±0.009), with impression scanning generating the most accurate models with a deviation of 0.022 mm (±0.007). CONCLUSIONS: The impression scanning method improved the precision of CAD-CAM-fabricated superstructures.

Implant therapy following liver transplantation: clinical and microbiological results after 10 years.

BACKGROUND: The number of immunocompromised patients is increasing as a consequence of successful organ transplantation. Placing dental implants in these patients has been questioned because of their increased risk for infections. The 10-year follow-up data of a 71-year-old liver transplant recipient with long-term immunosuppressive therapy is reported. Six months after liver transplantation, two interforaminal implants were inserted in the edentulous mandible, and an overdenture using non-rigid telescopic attachments was fabricated 3 months later. METHODS: Oral clinical parameters included the modified plaque index, sulcus fluid flow rate, modified bleeding index, probing depth, distance implant mucosa, attachment level, width of the keratinized mucosa and mobility values. The distance implant bone (DIB) was determined on digital panoramic radiographs. The levels of eight periodontal marker organisms were established using DNA probe technology. Additionally, swabs of the edentulous oral mucosa were taken for microbiological culture and antimicrobial resistance testing. RESULTS: The peri-implant parameters were within normal ranges indicating a stable osseointegration with moderate vertical bone loss. Actinobacillus actinomycetemcomitans, Tannerella forsythensis, Campylobacter rectus, and Treponema denticola were not detected. Low levels of Porphyromonas gingivalis, Fusobacterium nucleatum, and Eikenella corrodens were found. Prevotella intermedia was the only bacterium with a level higher than 10(4). The mucosal swabs indicated the presence of an abundant normal oral flora, including Escherichia coli and Candida albicans. The antibiogram revealed multiple resistance to antibiotics. CONCLUSION: This case report suggests that immunocompromised patients can be successfully rehabilitated with dental implants.