The association between gingival recession and buccal bone at maxillary anterior teeth.

BACKGROUND: Gingival recession and a thin or absent buccal plate occur frequently at maxillary anterior teeth and necessitate careful treatment planning to prevent future complications. However, the association between these two conditions is unclear and the ability of gingival recession to predict underlying buccal bone deficiencies is unknown. Therefore, the aim of this study is to use clinical and radiographic data to test this association and determine the influence of demographic and clinical parameters on both conditions. METHODS: This investigation comprised a single-center, retrospective study. Data were derived from periodontal examinations performed on 66 adult subjects. Corresponding cone-beam computed tomography images were used to measure the width of buccal bone at two points along the root surface and the distance between the bone crest and cemento-enamel junction (CEJ). Results were then analyzed to determine the association between the presence of gingival recession and the condition of radiographic buccal bone, as well as the relative contribution of demographic parameters and other clinical findings to gingival recession and buccal bone conditions. RESULTS: Gingival recession was present at 32.9% of maxillary anterior teeth and was most common at canines, followed by lateral incisors and central incisors. Mean buccal bone widths were significantly less, and the distance between the CEJ and bone crest was significantly greater for teeth with recession. Accordingly, gingival recession was a significant predictor for buccal bone thickness <1 mm at the level of 4 mm apical to the CEJ (odds ratio 2.733, 95% confidence interval 1.644 to 4.543, P < 0.0001). Probing depths were related to the presence or absence of gingival recession, while patient sex, age, and the apico-coronal height of the gingiva were related to buccal bone thickness. CONCLUSION: Within the limitations of this study, maxillary anterior teeth with pre-existing gingival recession were more likely to have thin (<1 mm) buccal bone.

In vitro shear bond strength of three self-adhesive resin cements and a resin-modified glass ionomer cement to various prosthodontic substrates.

OBJECTIVE: To evaluate the shear bond strength (SBS) of three self-adhesive resin cements and a resin-modified glass ionomer cement (RMGIC) to different prosthodontic substrates. MATERIALS AND METHODS: The substrates base metal, noble metal, zirconia, ceramic, and resin composite were used for bonding with different cements (n=12). Specimens were placed in a bonding jig, which was filled with one of four cements (RelyX Unicem, Multilink Automix, Maxcem Elite, and FujiCEM Automix). Both light-polymerizing (LP) and self-polymerizing (SP) setting reactions were tested. Shear bond strength was measured at 15 minutes and 24 hours in a testing device at a test speed of 1 mm/min and expressed in MPa. A Student t-test and a one-way analysis of variance (ANOVA) were used to evaluate differences between setting reactions, between testing times, and among cements irrespective of other factors. Generalized linear regression model and Tukey tests were used for multifactorial analysis. RESULTS: Significantly higher mean SBS were demonstrated for LP mode relative to SP mode (p<0.001) and for 24 hours relative to 15 minutes (p<0.001). Multifactorial analysis revealed that all factors (cement, substrate, and setting reaction) and all their interactions had a significant effect on the bond strength (p<0.001). Resin showed significantly higher SBS than other substrates when bonded to RelyX Unicem and Multilink Automix in LP mode (p<0.05). Overall, FujiCEM demonstrated significantly lower SBS than the three self-adhesive resin cements (p<0.05). CONCLUSIONS: Overall, higher bond strengths were demonstrated for LP relative to SP mode, 24 hours relative to 15 minutes and self-adhesive resin cements compared to the RMGICs. Bond strengths also varied depending on the substrate, indicating that selection of luting cement should be partially dictated by the substrate and the setting reaction.