This study was undertaken to understand the biodegradation mechanisms of calcium phosphate (Ca-P) biomaterials with different crystallization. Two types of sintered Ca-P porous ceramic (HA and beta-TCP) and a Ca-P bone cement (CPC) were implanted into cavities drilled in rabbit femoral and tibiae condyles. The results have shown that a material biodegradation was rapid in the beta-TCP and the CPC, but very weak in the HA. This biodegradation presented a decrease of material volume from the periphery to the center as well as a particle formation causing phagocytosis by numerous macrophages and multinucleated giant cells in the CPC. In the beta-TCP, there was a peripheral and central decrease of material volume as well as an absence of particle formation or visible phagocytosis. The process of biodegradation is considered to be directly influenced by the type of material crystallization. The sintered bioceramics processed at a high temperature exhibit good crystallization and are primarily degraded by a process dependent on interstitial liquids. However, the bone cement is formed by physicochemical crystallization and is degraded through a dissolution process associated with a cellular process.

ObjectivesA multicentric randomized, 3-year prospective study was conducted to determine for how long Biodentine, a new biocompatible dentine substitute, can remain as a posterior restoration.Materials and methodsFirst, Biodentine was compared to the composite Z100®, to evaluate whether and for how long it could be used as a posterior restoration according to selected United States Public Health Service (USPHS)’ criteria (mean ± SD). Second, when abrasion occurred, Biodentine was evaluated as a dentine substitute combined with Z100®.ResultsA total of 397 cases were included. This interim analysis was conducted on 212 cases that were seen for the 1-year recall. On the day of restoration placement, both materials obtained good scores for material handling, anatomic form (0.12 ± 0.33), marginal adaptation (0.01 ± 0.10) and interproximal contact (0.11 ± 0.39). During the follow-up, both materials scored well in surface roughness (≤1) without secondary decay and post-operative pain. Biodentine kept acceptable surface properties regarding anatomic form score (≤1), marginal adaptation score (≤2) and interproximal contact score (≤1) for up to 6 months after placement. Resistance to marginal discoloration was superior with Biodentine compared to Z100®. When Biodentine was retained as a dentine substitute after pulp vitality control, it was covered systematically with the composite Z100®. This procedure yielded restorations that were clinically sound and symptom free.ConclusionsBiodentine is able to restore posterior teeth for up to 6 months. When subsequently covered with Z100®, it is a convenient, efficient and well tolerated dentine substitute.Clinical relevanceBiodentine as a dentine substitute can be used under a composite for posterior restorations.

This study compared the in vitro marginal integrity of open-sandwich restorations based on aged calcium silicate cement versus resin-modified glass ionomer cement. Class II cavities were prepared on 30 extracted human third molars. These teeth were randomly assigned to two groups (n = 10) to compare a new hydraulic calcium silicate cement designed for restorative dentistry (Biodentine, Septodont, Saint Maur des Fossés, France) with a resin-modified glass ionomer cement (Ionolux, Voco, Cuxhaven, Germany) in open-sandwich restorations covered with a light-cured composite. Positive (n = 5) and negative (n = 5) controls were included. The teeth simultaneously underwent thermocycling and mechanocycling using a fatigue cycling machine (1,440 cycles, 5–55°C; 86,400 cycles, 50 N/cm2). The specimens were then stored in phosphate-buffered saline to simulate aging. After 1 year, the teeth were submitted to glucose diffusion, and the resulting data were analyzed with a nonparametric Mann-Whitney test. The Biodentine group and the Ionolux group presented glucose concentrations of 0.074 ± 0.035 g/L and 0.080 ± 0.032 g/L, respectively. No statistically significant differences were detected between the two groups. Therefore, the calcium silicate-based material performs as well as the resin-modified glass ionomer cement in open-sandwich restorations.

A surgical technique involving a resorbable membrane was used to treat 3 to 7 mm localized human buccal recessions on 10 consecutive patients. The exposed root surface was scaled and a trapezoidal mucoperiosteal flap was elevated after de-epithelization of the papillae. The space between the root and the membrane was created using a bur to form a concavity on the root and by bending the membrane with a suture. The flap was positioned as coronally as possible covering the membrane. The sutures were removed 15 days postsurgery and tetracycline therapy prescribed for 10 days. The results were evaluated at 12 months. The surgical procedure resulted in a significant reduction in recession (2.9 mm +/- 1.3) as well as a gain in attachment (3.4 mm +/- 2.1). Calculation of mean root coverage was 59.6%. There was no significant change of the keratinized tissue width. For therapeutic reasons, re-entry was performed in 2 cases: newly formed tissue was observed on the previously exposed roots. Guided tissue regeneration using a resorbable membrane appears to provide good results in cases of localized buccal recession.

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