Anterior implant restorations with a convex emergence profile increase the frequency of recession: 12-month results of a randomized controlled clinical trial.

AIM: To test whether the emergence profile (CONVEX or CONCAVE) of implant-supported crowns influences the mucosal margin stability up to 12 months after insertion of the final restoration. MATERIALS AND METHODS: Forty-seven patients with a single implant in the anterior region were randomly allocated to one of three groups: (1) CONVEX (n = 15), implant provisional and an implant-supported crown both with a convex profile; (2) CONCAVE (n = 16), implant provisional and an implant-supported crown both with a concave profile; (3) CONTROL (n = 16), no provisional (healing abutment only) and an implant-supported crown. All patients were recalled at baseline, 6, and 12 months. The stability of mucosal margin along with clinical, aesthetic, and profilometric outcomes as well as time and costs were evaluated. To predict the presence of recession, multivariable logistic regressions were performed and linear models using generalized estimation equations were conducted for the different outcomes. RESULTS: Forty-four patients were available at 12 months post-loading. The frequency of mucosal recession amounted to 64.3% in group CONVEX, 14.3% in group CONCAVE, and 31.4% in group CONTROL. Regression models revealed that a CONVEX profile was significantly associated with the presence of recessions (odds ratio: 12.6, 95% confidence interval: 1.82-88.48, p = .01) compared with the CONCAVE profile. Pink aesthetic scores amounted to 5.9 in group CONVEX, 6.2 in group CONCAVE, and 5.4 in group CONTROL, with no significant differences between the groups (p = .735). Groups CONVEX and CONCAVE increased the appointments and costs compared with the CONTROL group. CONCLUSIONS: The use of implant-supported provisionals with a CONCAVE emergence profile results in a greater stability of the mucosal margin compared with a CONVEX profile up to 12 months of loading. This is accompanied, however, by increased time and costs compared with the absence of a provisional and may not necessarily enhance the aesthetic outcomes. TRIAL REGISTRATION: German Clinical Trials Register; DRKS00009420.

Restorative angle of zirconia restorations cemented on non-original titanium bases influences the initial marginal bone loss: 5-year results of a prospective cohort study.

AIM: To assess radiographic, restorative, clinical and technical outcomes as well as patient satisfaction of directly veneered zirconia restorations cemented on non-original titanium bases over 5 years. MATERIAL AND METHODS: Twenty-four patients with a single missing tooth in the aesthetic zone were recruited. All patients received a two-piece implant with a screw-retained veneered zirconia restoration cemented extraorally on a titanium base abutment. Marginal bone levels (MBL), marginal bone changes, technical complications, patient satisfaction and clinical parameters including probing depth, bleeding on probing and plaque index were assessed at crown delivery (baseline), at 1 year (FU-1) and 5 years (FU-5) of follow-up. To investigate the relationship between restorative angle and MBL as well as marginal bone changes (bone loss/bone gain), correlation tests and linear regression models were carried out. RESULTS: Twenty-two patients were available for re-examination at 5 years. The mean MBL amounted to 0.54 ± 0.39 mm at baseline, and to 0.24 ± 0.35 at FU-5 (=bone gain) (p < .001). At FU-1, a positive correlation (r = .5) between the mesial restorative angle and mesial MBL was found (p = .012). Marginal bone changes between baseline and FU-1 at mesial sites were also positively correlated with the mesial restorative angle (r = .5; p = .037). Linear and logistic regression models confirmed that mesial marginal bone loss was significantly associated with the mesial restorative angle at FU-1 (p < .05). At 5 years, these significant associations at mesial sites disappeared (p > .05). At distal sites, no correlations or associations between the restorative angle and MBL or marginal bone changes were found regardless of the time point. During the 5-year follow-up, 5 technical complications occurred, mainly within the first year and mostly chippings. All patients were entirely satisfied with their implant-supported restoration at 5 years. CONCLUSION: Within the limitations of the present study, the restorative angle of implant-supported crowns on non-original titanium bases might influence the initial marginal bone loss but without affecting their favourable long-term clinical performance. A restorative angle of <40° may limit the initial marginal bone loss at implant-supported crowns with titanium bases.

Early versus late alveolar bone grafting in unilateral cleft lip and palate: Dental arch relationships in pre-adolescent patients.

OBJECTIVE: To evaluate the dental arch relationship in preadolescent children with complete unilateral cleft lip and palate after early secondary alveolar bone grafting (E-ABG) by comparing to late bone grafting (L-ABG). MATERIAL AND METHODS: Two raters blindly assessed the dental arch relationship with the modified Huddart-Bodenham (HB) Index for 2 groups: E-ABG group (36 children, mean age 9.6 years) and L-ABG group (56 children, mean age 11.1 years). The groups differed with respect to age at which alveolar bone grafting was performed: between 1.4 and 4.1 years (mean 2.2 years, E-ABG group) and after 8 years (L-ABG group). T-test was run to compare scores between 2 groups. Regression analysis was carried out to evaluate gender, age at cleft repair, age at ABG, and age at assessment with the HB index. RESULTS: The overall HB scores were -6.77 and -4.25 in the E-ABG and L-ABG groups, respectively (p = 0.025). Regression analysis showed that only the age at cleft repair influenced the HB scores. CONCLUSION: ABG carried out between 2 and 4 years of age does not seem to negatively affect the dental arch relationship at the age of 10 years in comparison to L-ABG.