Enamel matrix proteins in the regenerative therapy of deep intrabony defects

AIM

This prospective multicentre randomized controlled clinical trial was designed to compare the clinical outcomes of papilla preservation flap surgery with or without the application of enamel matrix proteins (EMD).

MATERIAL AND METHODS

172 patients with advanced chronic periodontitis were recruited in 12 centers in 7 countries. All patients had at least one intrabony defect of > or =3mm. Heavy smokers (> or =20 cigarettes/day) were excluded. The surgical procedures included access for root instrumentation using either the simplified or the modified papilla preservation flap in order to obtain optimal tissue adaptation and primary closure. After debridement, roots were conditioned for 2 min with a gel containing 24% EDTA. EMD was applied in the test subjects, and omitted in the controls. Postsurgically, a strict plaque control protocol was followed. At baseline and 1 year following the interventions, clinical attachment levels (CAL), pocket probing depths (PPD), recession (REC), full-mouth plaque scores and full-mouth bleeding scores were assessed. A total of 166 patients were available for the 1-year follow-up.

RESULTS

At baseline, 86 test and 86 control patients presented with similar subject and defect characteristics. On average, the test defects gained 3.1+/-1.5 mm of CAL, while the control defects yielded a significantly lower CAL gain of 2.5+/-1.5 mm. Pocket reduction was also significantly higher in the test group (3.9+/-1.7 mm) when compared to the controls (3.3+/-1.7 mm). A multivariate analysis indicated that the treatment, the clinical centers, cigarette smoking, baseline PPD, and defect corticalisation significantly influenced CAL gains. A frequency distribution analysis of the studied outcomes indicated that EMD increased the predictability of clinically significant results (CAL gains > or =4 mm) and decreased the probability of obtaining negligible or no gains in CAL (CAL gains <2 mm).

CONCLUSIONS

The results of this trial indicated that regenerative periodontal surgery with EMD offers an additional benefit in terms of CAL gains, PPD reductions and predictability of outcomes with respect to papilla preservation flaps alone.

Strength and marginal fit of full and partial porcelain crowns on Brånemark implants

The aim of the present study was to evaluate strength and marginal fit of different designed single crowns screwed on titanium implants (Brånemark) without the usage of any abutment. Seven test groups with 10 specimens each (standardized maxillary central incisor crowns) were fabricated of Empress (staining/veneering technique), metal-based Empress (staining/veneering technique), metal-based In-Ceram and metal ceramic (with/without cervical porcelain margin). The marginal fit of 5 specimens of each group was evaluated (SEM-Analysis) and the crowns were incisally loaded at a 30 degrees angle in a Zwick testing machine until fracture. The 5 remaining specimens underwent a marginal evaluation (SEM-analyses) before and after thermo-mechanical stressing (tms) and were loaded in the Zwick testing machine as well. All Empress ceramic crowns without metal reinforcement fractured during fixing procedure on the implant (32 N cm). The gap medians of the fixed crowns ranged from 11 microns (metal ceramic crowns) to 34 microns (metal ceramic crowns with porcelain margin). No significant differences in gap width were observed before and after tms. In the strength analyses screw-binding forces (SBF) of about 135 N were registered in all test groups. Fracture failure forces (FFF) reached up to 280 N. The indication of the crown designs presented in this study is limited in clinical use because of low stability and esthetics.