[Effect of acid etching time on bonding interface of non-carious cervical sclerotic dentin].

OBJECTIVE: To examine the effect of acid etching time on the bonding interface of non-carious cervical sclerotic dentin. METHODS: Twenty extracted premolars with non-carious cervical lesions were randomly divided into two groups, the lesion surface was conditioned with Scotchbond Multi-Purpose Plus dentin bonding system. The etching time was 15 s and 30 s respectively. The bonding interface ultrastructures were compared with SEM. RESULTS: In sclerotic dentin (15 s), the hybrid layer was visible, with minimal resin tags in the dentinal tubules and, when presented, they were shorter. Doubling the etching time (30 s) resulted in more resin tags with an hybrid layer formation on peritubular dentin. CONCLUSION: Doubling the etching time improved the ultrastructure of sclerotic dentin-resin bonding interface, and could be an efficient way to improve the bonding effect.

[Ultrastructural study of sclerotic dentin in non-carious cervical lesions disposed by a total-etching dentin adhesive].

OBJECTIVE: To examine the ultrastructure of resin-infiltrated sclerotic dentine following the application of a three-step total-etching dentin adhesive. METHODS: Naturally-occurring, non-carious cervical lesions on extracted premolars were bonded using a total-etching dentin adhesive-Scotchbond Multi-purpose. Artificially prepared wedge-shaped lesions were also made in sound premolars and restored using the same adhesive as control. The morphological change of the dentin surface conditioned with the etchant, and the hybrid zone and resin tags in the dentin-resin interface were studied by SEM. RESULTS: Most dentinal tubules were obliterated by rod-like sclerotic casts in the non-carious cervical lesion, and could not be dissolved by Scotchbond Multi-purpose etchant. Both the hybrid zone and resin tags were observed in sclerotic dentin after restoration, although the resin tags were fewer and in lack of communications, the length of resin tags and the thickness of the hybrid zone were almost similar to those of the sound dentin. CONCLUSION: Bonding to sclerotic dentin is different from sound dentin, and may be compromised by the fewer resin tags and communications.

[Immediate implantation of an abutment tooth attached by a magnet in an overdenture: report of one case].

A female patient, aged 59 years old, underwent immediate implantation of the abutment tooth attached by a magnet in an overdenture. The tooth recovered to normal three months later. A denture was remade and the tooth was still attached by a magnet at the same time. The overdenture fixed well 20 months later, and the tooth was normal. Results of X-ray examination was negative.

[Micro-tensile bond strength to sclerotic dentin in non-carious cervical lesions].

OBJECTIVE: This in vitro study was to evaluate the micro-tensile bond strength (microTBS) of three adhesives to sclerotic dentin in non-carious cervical lesions. METHODS: The maxillary premolars extracted due to periodontitis and with non-carious cervical lesions were collected. The non-carious, natural cervical sclerotic lesions were bonded with a total-etching adhesive Scotchbond Multi-Purpose, a two-step self-etching adhesive Contax, and an all-in-one self-etching adhesive Adper Prompt L-Pop. Artificially prepared wedge-shaped lesions were also made in sound premolars and bonded with the same adhesives as the controls. MicroTBS of these three adhesives was measured. RESULTS: MicroTBS of Scotchbond and Contax to sclerotic dentin was significantly lower than to normal dentin. But microTBS of Adper Prompt L-Pop to normal dentin was significantly lower than to sclerotic dentin. MicroTBS to sclerotic dentin was Scotchbond 46.805 MPa, Adper Prompt L-Pop 39.045 MPa, and Contax 29.852 MPa. CONCLUSIONS: In sclerotic dentin the microTBS was decreased because of the inferior micro-morphology of resin tags. Adhesives with low pH value might bond to sclerotic dentin effectively.

[Ultrastructural study of a self-etching adhesive to sclerotic dentin in non-carious cervical lesions].

OBJECTIVE: To examine, in vitro study, the ultrastructure of resin-infiltrated sclerotic dentine following the application of a two-step self-etching dentin adhesive. METHODS: Non-carious, natural cervical sclerotic lesions were bonded using Contax (DMG Hamburg, Germany), a self-etching dentin adhesive. Artificially prepared wedge-shaped lesions were also made in sound bicuspids and bonded using the same adhesive as controls. By SEM examination, the morphological change of the dentin surface treated by Contax Primer, and the hybrid layer and resin tag in the dentin-resin interface were studied. RESULTS: Most dentinal tubules were occluded by rod-like sclerotic casts in the sclerotic dentin surface. Both hybrid layer and resin tag were observed in sclerotic dentin. The hybrid layer was almost similar to that in the sound dentin, but the resin tags were shorter than those in controls. CONCLUSIONS: Bonding to sclerotic dentin is different from sound dentin and may be compromised by occluded dentin tubules. Based on the present ultrastructural features of hybrid layer and resin tags, the Contax, a self-etching dentin adhesive with a low pH value primer, may have some bonding efficacy to sclerotic dentin.