Does new bone formation vary in different sites within the same maxillary sinus after lateral augmentation? A prospective histomorphometric study

Objective The aim of this study was to evaluate histomorphometric outcomes of lateral maxillary sinus augmentation in different areas of the same cavity and to correlate results to bucco-palatal sinus width (SW) and residual bone height (RBH). Material and Methods Patients needing maxillary sinus floor elevation (RBH <5 mm) to insert two not adjacent implants were treated with lateral augmentation using a composite graft. Six months later, two bone-core biopsies (mesial/distal) were retrieved in implant insertion sites. SW and RBH were measured on cone beam computed tomography, and correlations between histomorphometric and anatomical parameters were evaluated by multivariate linear regression analysis. Results Twenty patients underwent sinus augmentation and eighteen were included in the final analysis (two dropouts for membrane perforation). Mean newly-formed mineralized tissue percentage (%NFMT) after 6 months in mesial and distal sites were 17.5 ± 4.7 and 11.6 ± 4.7, respectively (p=0.0004). Multivariate linear regression showed a strong negative correlation between SW and %NFMT (β coefficient=-0.774, p<0.0001), and no correlation between RBH and %NFMT (β coefficient =-0.038, p=0.825). Conclusions The present study confirms that %NFMT after lateral sinus augmentation occurs at different rates in different anatomical areas of the same maxillary sinus, showing a strong negative correlation with SW, whereas no influence of RBH was observed. Clinicians should regard SW as a guide for graft selection and to decide duration of the healing period. Researchers should consider SW as a predictor variable, when comparing regenerative outcomes of different biomaterials by using maxillary sinus as an experimental model.