Retention of bonded titanium copings fixed to implant abutments.

STATEMENT OF PROBLEM: Conical abutments can be laser welded to the abutment base to compensate for differing implant axes. As laser welding requires expensive equipment, alternative methods for bonding the conical abutment part with the abutment base should be considered. PURPOSE: The purpose of this in vitro study was to evaluate the retention of Ti-6Al-7Nb copings bonded adhesively to Ti-6Al-7Nb abutments and to compare it with the stability achieved by laser welding. MATERIAL AND METHODS: A total of 104 two-part Ti-6Al-7Nb specimens were prepared and divided into 13 groups with 8 specimens each. In this 2-part study, 3 luting resins (Panavia F 2.0 [PF]; Multilink Automix [MA]; Superbond C&B [SB]) were used with or without metal priming (PR). The laser welding group (LW) served as the control. After storage for 1 or 150 days (150 days with thermal cycling [TC]), push-out retention and welded joint stability were tested. The data were analyzed with ANOVA and the Tukey HSD multiple comparison tests. RESULTS: The choice of resin, thermal cycling, and metal priming had a significant effect on resin push-out retention. LW provided the strongest retention, followed by PF, MA, and SB. For PF and SB, TC decreased retention. PR did not lead to higher retention but provided better bonding stability when TC was applied. CONCLUSIONS: The retention values suggest that considering the maximum mastication forces, resin bonding is an appropriate substitute for the laser welding method.

Influence of dental education on esthetic perception.

AIM: One of the most challenging tasks in daily practice when it comes to defining treatment goals and how to attain them is the communication with the patient and the self-reflection of the treating dentist. Failures due to mis-communication are common, especially in esthetic dentistry. The purpose of this study was to evaluate the influence of dental education on students' and dentists' judgment of patients' dental appearance. MATERIALS AND METHODS: Based on internationally accepted guidelines about dental esthetics, a questionnaire was developed to measure "dental appearance" (QDA). Eleven items defined a QDA score (0 = "absolutely dissatisfied", 100 = "absolutely satisfied"). The QDA was completed by 29 patients (21 women, 8 men) before and after a complete oral rehabilitation, including restoration of the anterior teeth. Overall, 95 students (1st, 5th, and 10th Semester) and 30 dentists evaluated the patients' esthetics before and after rehabilitation on a visual analog scale (VAS; 0 = "absolutely unesthetic", 100 = "absolutely esthetic"). RESULTS: Students and dentists alike judged a significant esthetic improvement after treatment (P ≤ 0.0001). Significant differences could be found when comparing the students' and dentists' judgment and the patients' self-evaluation (P ≤ 0.05). CONCLUSION: Since it seems that students judge dental appearance differently from patients' self-assessment, teaching esthetic rules at university should incorporate the aspect of patient feedback in order to avoid misconceptions.

Patients' and dentists' perception of dental appearance.

The purpose of this study was to compare the patients' and dentists' perception of dental appearance. Based on internationally accepted guidelines about dental esthetics, a questionnaire was developed to measure "dental appearance" (QDA). Eleven items defined a QDA sum score (0 = "absolutely satisfied", 44 = "absolutely dissatisfied"). The QDA was completed by 16 patients (eight women, eight men, mean age 63 ± 9 years) before and after a complete oral rehabilitation. Forty-two dentists evaluated the esthetics before and after rehabilitation on a visual analog scale (VAS, 0 = "absolutely unesthetic", 100 = "absolutely esthetic"). The patients' quoting showed a significant esthetic improvement (QDA sum score) from 22 before treatment to 3.5 after treatment (P ≤ 0.001). Although most of the dentists judged an improvement in most of the patients dental appearances, no significant correlation could be found between patients' and dentists' judgment regarding dental appearance (r = -0.13-0.53, P > 0.05). When evaluating the influence of age, gender, and experience on rating dental appearance, no significant differences (P > 0.05) could be found.