Digital and Analog Analysis of Occlusion in Conventional and Implant-Retained Complete Dentures: Preliminary Results of a Prospective Clinical Trial.

PURPOSE: To digitally evaluate the static and dynamic occlusion of patients treated with both removable conventional complete dentures (CCDs) and implant-retained removable overdentures (IODs) and to correlate two different methods of occlusal analysis. MATERIALS AND METHODS: Eleven totally edentulous patients were treated with bimaxillary CCDs. Later, mandibular CCDs were replaced by IODs retained by either two or four implants. The distribution of the occlusal contacts in static and dynamic occlusion was compared by means of the digital method (DM; T-Scan III) and the analog method (AM; articulating paper). Scores 0, 1, and 2 were assigned for inadequate, satisfactory, and adequate distribution of the occlusal contacts, respectively. The frequencies of scores were compared in relation to the types of denture by means of Fisher exact test (P < .05). The correlation between methods was assessed by means of the kappa agreement coefficient (κ) and the correlation coefficient phi (φ) (P < .05). RESULTS: Significant differences between CCDs and IODs were found in the right lateral mandibular movement (DM, P = .024; AM, P = .008), as well as in the left lateral mandibular movement (DM, P = .035). The methods of analysis of the occlusion showed a moderate agreement (κ = 0.604; P < .001) and a moderate correlation (φ = 0.605; P < .001). CONCLUSION: The digital and analog methods showed a significant agreement and moderate correlation, irrespective of the type of complete denture. The T-Scan III digital system seems to be a consistent and reproducible method to analyze occlusion.

Primary and Secondary Stability of Extrashort (4-mm) Implants in the Edentulous Mandible: Preliminary Results of a Prospective Clinical Trial.

PURPOSE: To compare the primary and secondary stability of conventional (≥ 8-mm) and extrashort (4-mm) implants in edentulous patients using different methods of assessment. MATERIALS AND METHODS: Patients underwent implant surgery and were randomly allocated into two groups: test, with two conventional implants in the anterior region and two extrashort (4-mm) implants in the posterior region; and control, with two conventional (≥ 8-mm) implants in the anterior region only. Primary stability (S1-implant placement) was assessed by insertion torque, implant stability quotient (ISQ, Osstell), and damping capacity (PTV, Periotest), while secondary stability (S221-21 days after S1; and S2clip-at prosthetic loading, ± 3 months after S1) was evaluated by ISQ and PTV. The statistical significance level was set at P < .05. RESULTS: Fifty conventional implants and 24 extrashort implants were placed in 25 patients. The overall survival rate was 97.3%. There was no statistically significant difference between the insertion torque of conventional and extrashort implants (P > .05). PTV values were significantly lower for conventional implants only at S2clip (P = .041). ISQ values were significantly greater for conventional implants at S1 (P = .004), whereas at S221 and S2clip, no differences were found (P = .413 and P = .490, respectively). Damping capacity showed no significant differences between S1-S2M21 and S1-S2clip. ISQ values showed a significant increase of stability between S1-S2clip, for conventional (P = .022) and extrashort (P = .005) implants, which was different from that observed between S1-S221. There was a moderate negative correlation between the PTV and ISQ variables (r = 0.5) of extrashort implants, and between the PTV and insertion torque (r = -0.3) of conventional implants. For extrashort implants, there was a null correlation between ISQ and torque (r = 0.0). There was a moderately positive correlation between ISQ and torque (r = 0.3) in the conventional implant group. CONCLUSION: The results suggest that extrashort and conventional implants present similar primary and secondary stability values and may similarly influence restorative protocols.