A multi-centre randomized controlled trial on alveolar ridge preservation with immediate or delayed implant placement: Need for soft-tissue augmentation.

AIM: To assess the impact of the timing of implant placement following alveolar ridge preservation (ARP) on the need for soft-tissue augmentation (STA) and to identify the risk factors for horizontal and vertical soft-tissue loss. MATERIALS AND METHODS: Patients with a single failing tooth in the anterior maxilla (15-25) were treated at six centres. Following tooth extraction, they were randomly allocated to the test group (immediate implant placement, IIP) or control group (delayed implant placement, DIP). ARP was performed in both groups and implants were immediately restored with an implant-supported provisional crown. Six months after tooth extraction and ARP, a panel of five blinded clinicians assessed the need for STA on the basis of anonymized clinical pictures and a digital surface model. Lack of buccal soft-tissue convexity and/or mid-facial recession qualified for STA. Pre-operative and 6-month digital surface models were superimposed to assess horizontal and vertical soft-tissue changes. RESULTS: Thirty patients were included per group (test: 20 females, 10 males, mean age 53.1; control: 15 females, 15 males, mean age 59.8). The panel deemed STA as necessary in 24.1% and 35.7% of the cases following IIP and DIP, respectively. The difference was not statistically significant (odds ratio [OR] = 1.77; 95% confidence interval [CI] [0.54-5.84]; p = .343). Loss of buccal soft-tissue profile was higher following DIP (estimated mean ratio = 1.66; 95% CI [1.10-2.52]; p = .018), as was mid-facial recession (mean difference [MD] = 0.47 mm; 95% CI [0.12-0.83]; p = .011). Besides DIP, regression analysis identified soft-tissue thickness (-0.57; 95% CI [-1.14 to -0.01]; p = .045) and buccal bone dehiscence (0.17; 95% CI [0.01-0.34]; p = .045) as additional risk factors for mid-facial recession. Surgeons found IIP significantly more difficult than DIP (visual analogue scale MD = -34.57; 95% CI [-48.79 to -20.36]; p < .001). CONCLUSIONS: This multi-centre randomized controlled trial failed to demonstrate a significant difference in the need for STA between IIP and DIP when judged by a panel of blinded clinicians. Based on objective soft-tissue changes, patients with thin buccal soft tissues, with a buccal bone dehiscence and treated with a delayed approach appeared particularly prone to soft-tissue loss.

Treatment of mandibular Class II furcations using bovine-derived bone xenograft with or without a collagen membrane: a randomized controlled trial.

OBJECTIVES: This randomized clinical trial aimed to compare the effects of a bovine-derived xenograft with (control group, CG) or without (test group, TG) a collagen membrane for the treatment of mandibular Class II furcations. METHOD AND MATERIALS: Nineteen patients presenting 32 furcations were included and randomly assigned to CG (n = 16) or TG (n = 16). At the 6-month follow-up (M6), 29 furcations were reevaluated. All clinical measurements were performed by the same investigator with a straight periodontal probe and a specially designed "modified Nabers probe" (both with 1-mm increments). The primary outcome was the improvement of the horizontal probing attachment level. According to the protocol, there was no re-entry at 6 months. RESULTS: Both vertical (at M6, CG: 2.4 ± 0.8 mm, TG: 2.7 ± 1.0 mm) and horizontal probing attachment levels, whether measured with a periodontal probe (at M6: CG: 3.4 ± 0.8 mm, TG: 3.2 ± 1.0 mm) or the "modified Nabers probe" (at M6: CG: 3.5 ± 1.1 mm, TG: 3.2 ± 1.0 mm), favorably evolved after 6 months. There was no significant difference for any of the measures performed (P > .05, unpaired t test). CONCLUSIONS: Both treatments were clinically effective with no statistically significant difference between them but as there was no histologic analysis, the amount of real regeneration could not be analyzed. This conclusion should be confirmed by longer follow-up periods.

Tooth Retrospective Dosimetry Using Electron Paramagnetic Resonance: Influence of Irradiated Dental Composites.

In the aftermath of a major radiological accident, the medical management of overexposed individuals will rely on the determination of the dose of ionizing radiations absorbed by the victims. Because people in the general population do not possess conventional dosimeters, after the fact dose reconstruction methods are needed. Free radicals are induced by radiations in the tooth enamel of victims, in direct proportion to dose, and can be quantified using Electron Paramagnetic Resonance (EPR) spectrometry, a technique that was demonstrated to be very appropriate for mass triage. The presence of dimethacrylate based restorations on teeth can interfere with the dosimetric signal from the enamel, as free radicals could also be induced in the various composites used. The aim of the present study was to screen irradiated composites for a possible radiation-induced EPR signal, to characterize it, and evaluate a possible interference with the dosimetric signal of the enamel. We investigated the most common commercial composites, and experimental compositions, for a possible class effect. The effect of the dose was studied between 10 Gy and 100 Gy using high sensitivity X-band spectrometer. The influence of this radiation-induced signal from the composite on the dosimetric signal of the enamel was also investigated using a clinical L-Band EPR spectrometer, specifically developed in the EPR center at Dartmouth College. In X-band, a radiation-induced signal was observed for high doses (25-100 Gy); it was rapidly decaying, and not detected after only 24 h post irradiation. At 10 Gy, the signal was in most cases not measurable in the commercial composites tested, with the exception of 3 composites showing a significant intensity. In L-band study, only one irradiated commercial composite influenced significantly the dosimetric signal of the tooth, with an overestimation about 30%. In conclusion, the presence of the radiation-induced signal from dental composites should not significantly influence the dosimetry for early dose assessment.