Significance of Posterior Maxilla Residual Bone Height on Implant Survival

Background: To our knowledge, presently there are no studies in the literature investigating the significance of residual bone height in posterior maxilla per se in implant survival. Objective: to evaluate if the residual native bone height in the posterior maxilla plays a role in the survival rate of endosseous dental implants placed in the augmented sinus. Material and Methods: Type of study: retrospective case control. A total of 42 implants (24 patients) are included. Exclusion criteria: 1) uncontrolled systemic disease and local conditions (diabetes, endodontic pathosis) 2) Patients with implants that failed after the stage II implant surgery. Patients' records from Tufts University School of Dental Medicine within the last five years are reviewed. The implants are grouped into the following categories: 1) implants placed in the posterior maxilla that survived at time of stage II implant surgery 2) implants placed in the posterior maxilla that failed at time of stage II implant surgery or earlier. The residual bone height is defined as the distance from the sinus floor to the alveolar ridge crest and determined by patients' periapical radiographs and/or CT scans. Statistical Analysis: Independent sample t-tests and chi squares are conducted to define if there is any statistically significant difference in the residual bone height and other tested parameters such as the location of implant, type of sinus lift, age and sex of the patient between the two groups Results: No statistical difference was found in the residual bone height between the two groups. The study had 80% power to determine a difference in the residual bone height of 2.215mm. Conclusions: Within the limits of this study the residual bone height did not play a significant role on implant survival. Further prospective studies are needed to acquire definitive conclusions.