Horizontal Ridge Expansion: A Comparative Study of Motorized Ridge Expanders Versus Osseodensification Techniques

Adequate horizontal and vertical bone volume is an ideal prerequisite to achieving good primary stability, osseointegration, and long-term survival of an implant. Several techniques are available to achieve adequate bone volume for implant placement. Among the various non-subtractive methods, ridge expansion with motorized bone expanders is a commonly used method to expand bone volume in the anterior maxilla. At the same time, osseodensification is another non-subtractive method that aims to improve primary stability.

This study aimed to compare the expansion achieved by the two most commonly used expansion methods, i.e., motorized bone expanders technique and a relatively newer technique of osseodensification suggested by Densah Bur (Jackson, Michigan, United States), for expanding the alveolar ridge in the anterior maxillary region.  Materials and methods: A total of 30 implants were placed in the anterior maxillary region in 15 patients. Fifteen implants were placed with the bone expander method (Dentium Ridge Spreader (RS) kit, Cypress, California, United States) and 15 with the osseodensification method (Densah® Bur). At least two implants were placed in each patient. The implants were placed in the first and second quadrants of the same patients in whom one of the methods was performed. Alveolar ridge expansion was determined using pre-op and post-op cone beam computed tomography (CBCT) instantly before implant placement and after six months. Primary stability was also analyzed using Osstell (Gothenburg, Sweden) immediately after implant placement and after one month and secondary stability after six months in implant stability quotient (ISQ). These parameters were used to assess which method promoted greater alveolar ridge expansion and primary stability.

The test for normality was performed using the Shapiro-Wilk test between the pre- and post-treatment data between group A (motorized ridge expander) and group B (osseodensification technique). There were p-values of 0.737 and 0.429, which were not significant. Bone thickness was measured both preoperatively and postoperatively among the groups. The mean bone thickness in group A was 4.37 mm preoperatively and 5.8 mm postoperatively. The similarity between the preoperative and postoperative bone thickness was 4.336 mm and 5.24 mm, respectively. For the bone measurements, the p-value <0.001 is highly significant. On further analysis, the p-value for the paired samples t-test for group A postoperative bone thickness and group B postoperative bone thickness was 0.894, and the p-value for the t-test for group A postoperative bone thickness and group B postoperative bone thickness was 0.955. ISQ was also analyzed. In group A, the mean ISQ one month postoperatively was 53.2 and six months postoperatively was 73.4. In group B, the mean ISQ one month postoperatively was 65.4 and six months postoperatively was 76.2. The p-value for the ISQ of group A was 0.004, the ISQ of group B was 0.023, and the ISQ of groups A and B in the first month was 0.015. In the sixth month, the ISQ in group A and group B was 0.592.  Conclusion: According to the results of the study, motorized ridge expanders proved to be more effective in terms of ridge expansions and achieving better primary stability than the osseodensification technique.