Four-unit fixed dental prostheses replacing the maxillary incisors supported by two narrow-diameter implants - a five-year case series.

OBJECTIVES: (1) To determine the survival rate of 10 four-unit fixed dental prostheses (FDPs) replacing the four maxillary incisors, supported by 20 narrow-diameter implants (NDIs), (2) to assess the incidence of mechanical and biological complications, and (3) to evaluate bone level changes longitudinally after final FDP insertion. MATERIALS AND METHODS: Ten patients (six women, four men), mean age 49.4 ± 12.6 years, were treated with a four-unit anterior maxillary FDP (six screw-retained; four cemented). Biological parameters, eventual technical complications, radiographic measurements, and study casts were assessed at 1 (baseline), 3, and 5 years after implant placement. A multilevel logistic regression test was performed on clinical parameters and bone level changes (significance level P < 0.05). RESULTS: The 5-year implant and FDP survival rate was 100%. Mean modified plaque index (mPI) values were 0.03 and 0.02 at 3 and 5 years, significantly lower when compared to mPI (0.11 ± 0.31) at 1 year. Mean modified sulcus bleeding index (mSBI) was 0.08, 0.08, and 0.15 over time. Probing depth (PD) values were 1.57, 1.64, and 2.03 mm. Statistically significant differences were found between 1 vs. 5 year (P = 0.0003) and 3 vs. 5 year (P = 0.001). Keratinized mucosa (3.65 mm) remained stable during observation period. DIB mean values were 2.01 ± 0.34, 2.13 ± 0.13, and 2.17 ± 0.38 mm. Patient satisfaction based on visual analog scale revealed favorable fulfillment of overall treatment and esthetic expectations. CONCLUSIONS: Two NDIs supporting a four-unit FDP to replace the four missing maxillary incisors may be considered a predictable treatment modality.

Malpositioned implants in the anterior maxilla: a novel restorative approach to reestablish peri-implant tissue health and acceptable esthetics. Part I. Case presentation and treatment options.

This two-part case presentation describes the prosthetic challenge of managing complications after inadequate esthetic risk assessment, treatment planning, and implant positioning in the anterior maxilla. Here, the case report of a 50-year-old woman, referred after inappropriate execution of immediate implant placement, is presented. Different restorative treatment alternatives are proposed, excluding major surgical procedures. In the next part of the article, the advantages and shortcomings of the various prosthetic options will be discussed and the selected treatment revealed. The aim of this part of the article is to illustrate the importance of treatment planning, emphasizing that the correction of esthetic implant failures consistently leads to compromised results when compared to what could have been achieved first time round.

Three- to nine-year survival estimates and fracture mechanisms of zirconia- and alumina-based restorations using standardized criteria to distinguish the severity of ceramic fractures.

OBJECTIVES: The aims of this study were set as follows: 1. To provide verifiable criteria to categorize the ceramic fractures into non-critical (i.e., amenable to polishing) or critical (i.e., in need of replacement) 2. To establish the corresponding survival rates for alumina and zirconia restorations 3. To establish the mechanism of fracture using fractography MATERIALS AND METHODS: Fifty-eight patients restored with 115 alumina-/zirconia-based crowns and 26 zirconia-based fixed dental prostheses (FDPs) were included. Ceramic fractures were classified into four types and further subclassified into "critical" or "non-critical." Kaplan-Meier survival estimates were calculated for "critical fractures only" and "all fractures." Intra-oral replicas were taken for fractographic analyses. RESULTS: Kaplan-Meier survival estimates for "critical fractures only" and "all fractures" were respectively: Alumina single crowns: 90.9 and 68.3 % after 9.5 years (mean 5.71 ± 2.6 years). Zirconia single crowns: 89.4 and 80.9 % after 6.3 years (mean 3.88 ± 1.2 years). Zirconia FDPs: 68.6 % (critical fractures) and 24.6 % (all fractures) after 7.2 and 4.6 years respectively (FDP mean observation time 3.02 ± 1.4 years). No core/framework fractures were detected. CONCLUSIONS: Survival estimates varied significantly depending on whether "all" fractures were considered as failures or only those deemed as "critical". For all restorations, fractographic analyses of failed veneering ceramics systematically demonstrated heavy occlusal wear at the failure origin. Therefore, the relief of local contact pressures on unsupported ceramic is recommended. Occlusal contacts on mesial or distal ridges should systematically be eliminated. CLINICAL RELEVANCE: A classification standard for ceramic fractures into four categories with subtypes "critical" and "non-critical" provides a differentiated view of the survival of ceramic restorations.

Malpositioned implants in the anterior maxilla: a novel restorative approach to reestablish peri-implant tissue health and acceptable esthetics. Part II: Case report and discussion.

This two-part case presentation describes the prosthetic challenge of managing complications in a 50-year-old female patient after inadequate esthetic risk assessment, treatment planning, and implant placement in the anterior maxilla. In Part I, the clinical situation was described, and different restorative solutions were proposed to correct the extreme facial inclination of the implants, excluding major surgical procedures, namely implant removal. In Part II, different prosthetic options are discussed, and the final treatment is revealed. A noninvasive treatment protocol was applied to transform a severely compromised postsurgical situation into an esthetically acceptable result. An unconventional prosthesis design was implemented, including the use of ceramic veneers bonded to the CAD/CAM-generated screw-retained zirconia- based fixed dental prosthesis (FDP), to correct major axis-related problems and spatial discrepancies.

Quantitative three-dimensional methodology to assess volumetric and profilometric outcome of subepithelial connective tissue grafting at pontic sites: a prospective pilot study.

The aim of this study was to describe a technique for the assessment of soft tissue volumetric and profilometric changes. The technique has been applied at the alveolar contour of mild to moderate horizontal ridge defects after soft tissue augmentation at pontic sites. A quantitative three-dimensional (3D) analysis based on laser scanning was used for the measurement of volume gain and horizontal changes of alveolar profile 5 months after a subepithelial connective tissue graft using a pouch approach in five patients. All the surgical sites healed uneventfully. A mean soft tissue volume increase of 35.9 mm3 was measured 5 months after the grafting procedure. The linear measurements showed that, in the area where the augmentation was performed, the distance between the preoperative vestibular profile and the postoperative one ranged from 0.16 to 2 mm. The described quantitative measurements based on 3D laser scanning appear to be an effective method for assessment of soft tissue changes in future studies. Additionally, within the limitation of a small sample size, the present data suggest that the investigated surgical technique can be considered when corrections of mild to moderate alveolar horizontal ridge atrophies at maxillary lateral incisor edentulous gaps are necessary.

Survival rates of short (6 mm) micro-rough surface implants: a review of literature and meta-analysis.

OBJECTIVE: The aim of this review was to test the hypothesis that 6 mm micro-rough short Straumann(®) implants provide predictable survival rates and verify that most failures occurring are early failures. MATERIALS AND METHODS: A PubMed and hand search was performed to identify studies involving micro-rough 6-mm-short implants published between January 1987 and August 2011. Studies were included that (i) involve Straumann(®) 6 mm implants placed in the human jaws, (ii) provide data on the survival rate, (iii) mention the time of failure, and (iv) report a minimum follow-up period of 12 months following placement. A meta-analysis was performed on the extracted data. RESULTS: From a total of 842 publications that were screened, 12 methodologically sound articles qualified to be included for the statistical evaluation based on our inclusion criteria. A total of 690 Straumann(®) 6-mm-short implants were evaluated in the reviewed studies (Total: placed-690, failed-25; maxilla: placed-266, failed-14; mandible: placed-364, failed-5; follow-up period: 1-8 years). A meta-analysis was performed on the calculated early cumulative survival rates (CSR%). The pooled early CSR% calculated in this meta-analysis was 93.7%, whereas the overall survival rates in the maxilla and mandible were 94.7% and 98.6% respectively. Implant failures observed were predominantly early failures (76%). CONCLUSION: This meta-analysis provides robust evidence that micro-rough 6-mm-short dental implants are a predictable treatment option, providing favorable survival rates. The failures encountered with 6-mm-short implants were predominantly early and their survival in the mandible was slightly superior.

Efficacy and predictability of short dental implants (<8 mm): a critical appraisal of the recent literature.

PURPOSE: This review of literature was conducted to evaluate the predictability of treatment outcomes with short dental implants (SDI), ie, implants shorter than 8 mm. MATERIALS AND METHODS: The review included studies, published between January 1990 and July 2011, that (1) involved SDI (<8 mm) placed in human jaws, (2) had a minimum of 20 SDI in their analysis, (3) provided data on survival rates, and (4) reported a minimum observation period of at least 3 months after placement. RESULTS: Forty-one studies fulfilled the above criteria; only 17 of these studies reported outcomes with microrough surface SDI. Six different lengths (4, 5, 6, 6.5, 7 and 7.5 mm) of microrough surface SDI with varying diameters (3.5 to 6 mm) were identified in the studies. A total of 1,828 microrough surface SDI were inserted and 45 failures were reported. Observation periods ranged from 3 months to 9 years. The reported survival rates for SDI ranged from 92.2% to 100%. From a total of 1,123 SDI inserted in specified jaw locations, failures were observed more often in the maxilla (n=297, failed=13) than in the mandible (n=826, failed=19). The review did not identify any correlation between implant diameter and survival for the microrough SDI. CONCLUSIONS: Microrough surface short implants (6 to 7.5 mm) appear to provide favorable survival rates and, therefore, can be predictably employed for simplification of implant therapy in situations of reduced alveolar heights in the posterior jaw segments.

The use of polytetrafluoroethylene tape for the management of screw access channels in implant-supported prostheses.

This article describes a procedure in which polytetrafluoroethylene (PTFE) tape is used to seal the screw access channel to protect the screw head of the abutment and crown screw in implant-supported restorations. The material can be sterilized, is easy to manipulate, radiopaque, and less associated with malodor when retrieved. Malodor is primarily associated with the implant-abutment interface configuration and the suprastructure component design of a given implant system. This technique enables fast removal of the filling material in a single piece, preventing unpredictable and time-consuming manipulations when removal of the screw-retained crown or abutment is required.