Is clinical experience important for obtaining the primary stability of dental implants with aggressive threads? An ex vivo study

Background: The aim of this study was to investigate the clinicians' experience on maintaining the primary stability of implants with aggressive threads belonging to a novel dental implant system. Material and Methods: Three hundred implants with aggressive threads were inserted in fresh bovine ribs mimicking Type IV bone by five clinicians which were classified according to their previous experience of total number of implant insertion. An independent examiner measured the primary stability of all implants after insertion by using resonance frequency analysis (RFA), electronic percussive testing (EPT) and removal torque methods. Results: No significant differences were detected between the stability values measured by the clinicians (p> 0.05) except the Periotest values (PTVs) of the non-experienced clinician. PTVs of the non-experienced clinician were significantly higher than the PTVs of the expert and good clinicians (p<0.05). Significantly higher stability values were detected in the secondary insertion of the non-experienced clinician as compared to her initial insertion values (p<0.05). No significant differences were detected between the first and second measurements of the other clinicians (p> 0.05). Conclusions: Within the limitations of this ex-vivo study, it may be concluded that experience does not play an important role in maintaining the stability of implants with aggressive threads

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Clinical Comparison of Screw-Retained and Screwless Morse Taper Implant-Abutment Connections: One-year Postloading Results.

PURPOSE: The purpose of this study was to clinically evaluate the screwless Morse taper implant-abutment connection type, in which the retention screw is totally eliminated, in terms of stability, success, periodontal parameters, and marginal bone levels after 1 year of function by comparing it with a passive fit internal implant-abutment connection, wherein a space exists between the matching components. MATERIALS AND METHODS: Each edentulous subject received an implant with a screwless Morse taper connection (MT) in the left canine area of the mandible and an implant with a screw-retained implant-abutment connection (SR) in the right canine area of the mandible. All implants were loaded 6 weeks later. All cases were restored with a cemented bar-retained mandibular overdenture opposing a maxillary complete denture. Clinical recalls at 6 months and 12 months postloading were scheduled and the MT and SR implants were compared in terms of success, survival, primary and secondary implant stability, marginal bone loss, soft tissue response, and mechanical complications. The results were statistically analyzed. RESULTS: A total of 20 subjects were included (10 females, 10 males; average age: 61.60 years) and a total of 40 implants were inserted. No implant failure or technical problem was detected for either MT or SR implants. Marginal bone loss around MT and SR implants did not show any significant differences at 6 weeks after surgery (time of loading) or at 6 months or 12 months postloading (P > .05). Periodontal parameters such as gingival index and probing pocket depth of MT and SR implants likewise did not differ significantly at 6 months and 12 months postloading (P > .05). Primary stability values of MT and SR implants did not differ significantly when measured with the insertion torque device (mean of 68.10 Ncm for MT and 64.20 Ncm for SR implants; P = .564), nor when measured with the electronic percussive testing device (mean of -5.30 for the MT and -5.35 for the SR implants; P = .398). However, MT implants showed lower stability at the time of loading (6 weeks) and 6 months postloading (P = .037 and P = .003, respectively). Stability values did not show any significant differences 12 months postloading (P > .05). CONCLUSIONS: Within the limitations of this clinical study, it can be concluded that implants with screwless Morse taper and passive fit internal connections show comparable technical and biologic results after 1 year of function.

Evaluation of possible prognostic factors for the success, survival, and failure of dental implants.

PURPOSE: To analyze the prognostic factors that are associated with the success, survival, and failure rates of dental implants. MATERIAL AND METHODS: Data including implant sizes, insertion time, implant location, and prosthetic treatment of 1656 implants have been collected, and the association of these factors with success, survival, and failure of implants was analyzed. RESULTS: The success rate was lower for short and maxillary implants. The failure rate of maxillary implants exceeded that of mandibular implants, and the failure rate of implants that were placed in the maxillary anterior region was significantly higher than other regions. The failure rates of implants that were placed 5 years ago or more were higher than those that were placed later. CONCLUSIONS: Anterior maxilla is more critical for implant loss than other sites. Implants in the anterior mandible show better success compared with other locations, and longer implants show better success rates. The learning curve of the clinician influences survival and success rates of dental implants.