Preserving the marginal bone level (MBL) is essential for the long-term success of dental implant therapy, and bone remodeling around dental implants is considered to vary with time. Numerous studies comparing the platform-switching (PS) and platform-matching (PM) dental implants have indicated that PS dental implants showed a lesser reduction for the MBL, and the majority of them had a relatively short period. This study aimed to evaluate vertical and horizontal bone defects by using digital periapical radiographs to examine the changes in MBL around PM and PS dental implants over 5 years after functional loading. The vertical MBL (vMBL) was measured from the implant–abutment junction to the first bone-to-implant contact. The horizontal MBL (hMBL) was measured from the implant–abutment junction to the bone crest. All data were presented as means ± standard errors. Paired and independent t-tests with Welch’s correction were used to analyze the data. A total of 61 dental implants in 38 patients after 5 years of functional loading were evaluated. Over time, PS dental implants were more likely to gain bone; by contrast, PM dental implants were more likely to lose bone during the observation time. Changes in vMBL for PS dental implants were significantly less than those for PM dental implants at 1-year (p = 0.045), 3-year (p = 0.021), and 5-year (p = 0.010) loading. Likewise, changes in hMBL for PS dental implants were significantly smaller than in those for PM dental implants at 3-year (p = 0.021) and 5-year (p = 0.006) loading; however, the changes were minimal in both approaches. PS dental implants had a significant increment in the percentage of bone integration, whereas that for PM dental implants dropped over time, with no significance. In PS dental implants that occlude with natural teeth, vertical and horizontal bone gain was observed, and it was significant at 3 years (p = 0.023). A significant horizontal bone gain was observed in the opposing natural teeth at 3-year (p = 0.002) and 5-year loading (p = 0.002). The PS concept appears to preserve more MBL around dental implants by stabilizing the vMBL and hMBL over a 5-year period. A minimal marginal bone change was detected in both concepts. The opposing natural teeth at PS dental implants showed a favorable effect on marginal bone tissues.

Background Alveolar osteitis (AO) may occur after molar extraction. Chlorhexidine (CHX) rinse and CHX gel are widely used to prevent AO. Although previous meta-analyses support the effectiveness of both CHX rinse and CHX gel in preventing AO, important issues regarding these two formulations have not been addressed adequately in the literature. Purpose A systematic review and meta-analysis of randomized controlled trials was conducted to determine the effectiveness of CHX rinse and CHX gel in preventing AO. Methods PubMed, EMBASE, SCOPUS, and Cochrane databases were searched for randomized controlled trials published before June 2018. The risk ratio (RR) was used to estimate the pooled effect of AO incidence using a random-effect model. Results The RRs of AO in patients treated with 0.12% CHX rinse (RR = 0.54, 95% CI [0.41, 0.72]) and 0.2% CHX rinse (RR = 0.84, 95% CI [0.52, 1.35]) were significantly lower than in those treated with the control. Moreover, a significantly lower RR was identified in patients treated with 0.2% CHX gel (RR = 0.47, 95% CI [0.34, 0.64]) than in those treated with the control. When CHX products of different concentrations were grouped together, patients treated with CHX rinse showed an RR of AO of 0.61 (95% CI [0.48, 0.78]) and those treated with CHX gel showed an RR of AO of 0.44 (95% CI [0.43, 0.65]). On the other hand, a meta-analysis of three trials that compared CHX rinse and CHX gel directly showed a significantly lower RR of AO in patients treated with CHX rinse than in those treated with CHX gel (RR = 0.56, 95% CI [0.34, 0.96]). Conclusions/Implications for Practice The results support the effectiveness of both CHX rinse and gel in reducing the risk of AO after molar extraction. Each formulation provides unique benefits in terms of ease of application and cost. On the basis of the results of this study, the authors recommend that CHX gel be used immediately after molar extraction because of the convenience and cost-effectiveness of this treatment and that CHX rinse be used by the patient after discharge at home in combination with appropriate health education and case management.

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