Relationship between Radiographic Misfit and Clinical Outcomes in Immediately Loaded Complete-Arch Fixed Implant-Supported Prostheses in Edentulous Patients.

PURPOSE: To examine if an uncorrected radiographically detected immediate postoperative misfit (implant level or abutment level) in immediately loaded conversion prosthesis plays a significant role in early implant or prosthesis failure. In addition, clinical characteristics related to type of arch, implant position, type of implant, implant orientation, type of connection, and type of surgery were analyzed relative to their relationship to early implant or prosthesis failure. MATERIALS AND METHODS: Immediate postoperative and subsequent follow-up panoramic radiographs of 425 arches with immediately loaded complete-arch fixed implant-supported prostheses were screened in a retrospective analysis. Implants with misfit and nonmisfit within a given arch were summarized separately with respect to each clinical characteristic and the difference between misfit and nonmisfit groups was tested using a mixed-effects logistic regression model with a patient-specific random intercept. A p-value <0.05 was determined to be statistically significant. RESULTS: A total of 2025 implants from 311 patients were identified in the 425 arches that were screened for radiographic misfit. A total of 48 implants with misfit were found within 33 arches (23 patients) for a 2.4% prevalence rate. Among the misfit implants, two failures were documented during the healing phase for an early implant survival rate of 95.8%. Five conversion prostheses with misfit fractured during the healing phase for early prosthesis survival rate of 84.8%. None of the clinical variables analyzed were significantly associated with the misfit status (p < 0.05). CONCLUSIONS: The results from this retrospective study showed that misfit in immediately loaded complete-arch fixed implant-supported prostheses may not play a detrimental role in the implant survival but may affect survival of the conversion prostheses.

A retrospective analysis of 800 Brånemark System implants following the All-on-Four™ protocol.

PURPOSE: The purpose of this study was to retrospectively evaluate implant survival rates in patients treated with the All-on-Four™ protocol according to edentulous jaws, gender, and implant orientation (tilted vs. axial). MATERIALS AND METHODS: All Brånemark System implants placed in patients following the All-on-Four™ protocol in a single private practice were separated into multiple classifications (maxilla vs. mandible; male vs. female; tilted vs. axial) by retrospective patient chart review. Inclusion criteria consisted of any Brånemark System implant placed with the All-on-Four™ protocol from the clinical inception (May 2005) until December 2011. Life tables were constructed to determine cumulative implant survival rates (CSR). The arches, genders, and implant orientations were statistically compared with ANOVA. RESULTS: One hundred fifty-two patients, comprising 200 arches (800 implants) from May 2005 until December 2011, were included in the study. Overall implant CSR was 97.3% (778 of 800). Two hundred eighty-nine of 300 maxillary implants and 489 of 500 mandibular implants survived, for CSRs of 96.3% and 97.8%, respectively. In male patients, 251 of 256 implants (98.1%) remain in function while 527 of 544 implants (96.9%) in female patients survived. Regarding implant orientation, 389 of 400 tilted implants and 389 of 400 axial implants osseointegrated, for identical CSRs of 97.3%. All comparisons were found to be statistically insignificant. The prosthesis survival rate was 99.0%. CONCLUSIONS: The results from this study suggest that edentulous jaws, gender, and implant orientation are not significant parameters when formulating an All-on-Four™ treatment plan. The high CSRs for each variable analyzed demonstrate the All-on-Four™ treatment as a viable alternative to more extensive protocols for rehabilitating the edentulous maxilla or mandible.

Brånemark system implant lengths in the pterygomaxillary region: a retrospective comparison.

PURPOSE: Implants that engage the cortical bone of the pterygomaxillary region help restore dentition to the posterior maxilla. However, proper implant length is required. The purpose of this study was to determine if there is a statistically significant difference in the survival rates between different sized implants placed in the pterygomaxillary region. MATERIALS AND METHODS: All Brånemark System 4.0-mm-diameter implants delivered into the pterygomaxillary region in a single private practice were separated into 7- to 13-mm and 15- to 18-mm groups by retrospective patient chart review. Cumulative survival rates (CSR) were calculated. RESULTS: Of all implants delivered, 930 of the 992 osseointegrated for a CSR of 93.75%. Fifty-nine of the 67 implants in the 7- to 13-mm grouping and 871 of the 925 implants in the 15- to 18-mm grouping osseointegrated for CSRs of 88.06% and 94.16%, respectively. The results were statistically significant (P < 0.05). CONCLUSIONS: The results suggest that increased implant length in the pterygomaxillary region may result in higher osseointegration rates. The implant apex better engages the cortical bone between the medial and lateral pterygoid plates and therefore increases primary and secondary stability.

A retrospective comparison of implants in the pterygomaxillary region: implant placement with two-stage, single-stage, and guided surgery protocols.

PURPOSE: Implants placed into the pterygomaxillary region allow for increased posterior support and a full complement of teeth without the need for distal cantilevers. With advancements in research and technology, implant delivery has evolved from the traditional two-stage procedure to immediate loading freehand and guided surgical template protocols. The purpose of this retrospective study is to determine if there is a significant difference in implant survival rates between these protocols. MATERIALS AND METHODS: All pterygomaxillary implants placed in a single private practice from September 1985 to July 2011 were categorized into three separate classifications (two-stage freehand, single-stage freehand, or single-stage guided) by retrospective chart review. Life tables were constructed to determine the cumulative survival rates (CSR), and ANOVA was used to identify statistical significance. RESULTS: A total of 981 patients comprising 371 males and 610 females were included in the study. Of all pterygomaxillary implants, 1,460 of 1,608 implants osseointegrated for a CSR of 90.80%. Seven hundred nine of the 825 two-stage, 624 of the 647 single-stage, and 127 of the 136 guided surgery implants osseointegrated for CSRs of 85.94%, 96.45%, and 93.38%, respectively. The comparison between two-stage and single-stage protocols was statistically significant, (P < .05) while the difference between single-stage guided versus freehand protocols was found to be statistically insignificant (P > .05). CONCLUSION: The results from this retrospective study reinforce that immediate loading of pterygomaxillary implants with a provisional prosthesis is beneficial to both doctor and patient. The lower CSR for the guided surgery protocol compared with the single-stage freehand procedure is statistically insignificant, suggesting guided surgery is still a viable and recommended option for qualified patients.