Discussion

The present study evaluated the effect of osseodensification on peri-implant bone density and alveolar ridge width in D3 and D4 bone of the posterior maxilla. The posterior maxilla is clinically challenging because it commonly presents with low-density trabecular bone, reduced ridge dimensions, and limited mechanical resistance during implant insertion [4]. As primary stability is strongly influenced by local bone quality and density, improving the peri-implant bone environment is particularly important in D3 and D4 bone [3].

The immediate postoperative CBCT demonstrated the presence of compacted autogenous bone chips surrounding the implant osteotomy. These preserved bone particles are characteristic of the osseodensification technique and may act as an autografting substrate, potentially contributing to increased peri-implant bone density and improved osseointegration observed during the healing period (Figure 5).

Figure 5: Representative immediate postoperative cone-beam computed tomography image demonstrating compacted autogenous bone chips (arrow) surrounding the implant following osseodensification.

The results of the present study showed a progressive increase in peri-implant bone density in both D3 and D4 bone groups following osseodensification. This supports the principle that osseodensification preserves and compacts bone rather than removing it during osteotomy preparation [7]. In D3 bone, the mean peri-implant bone density increased from 481.5 ± 99.5 HU preoperatively to 689.4 ± 193.7 HU at four months. In D4 bone, the mean density increased from 332.9 ± 78.1 HU preoperatively to 588.7 ± 105.6 HU at four months. This increase indicates that osseodensification produced both an immediate densifying effect and continued improvement during the healing period.

Lahens et al. reported improved biomechanical fixation and increased bone-to-implant contact after osseodensification in low-density bone [8]. Bandela et al. reported improved primary stability with osseodensification compared with conventional osteotomy preparation in an ex vivo study [5]. Aloorker et al. also observed improvement in bone density and maintenance of crestal bone levels after osseodensification in a split-mouth clinical study [11]. The findings of the present study are consistent with these observations, as both D3 and D4 bone showed increased peri-implant bone density after osseodensification.

An important finding of this study was that D3 bone showed significantly higher bone density than D4 bone at baseline and immediately after implant placement, but the difference was no longer statistically significant at four months. This suggests that osseodensification may exert a particularly beneficial effect in poorer quality bone. Although D3 bone had higher absolute density values, D4 bone demonstrated a substantial relative improvement over time. Clinically, this may be relevant because D4 bone is generally more compromised and more difficult for achieving predictable implant stability.

The present study also showed measurable alveolar ridge expansion in both bone groups. In D3 bone, mean ridge width increased from 8.2 mm preoperatively to 9.8 mm at four months, while in D4 bone, it increased from 8.0 mm to 8.8 mm. Koutouzis et al. demonstrated that osseodensification can produce alveolar ridge expansion through plastic deformation and compaction autografting [9]. Salman and Bede reported that osseodensification enabled ridge expansion and implant placement in narrow alveolar ridges without dehiscence or fenestration [10]. The present study supports these findings and shows that osseodensification can produce clinically measurable dimensional changes in posterior maxillary bone.

The level-wise findings showed that ridge expansion was more pronounced at L2 and L3 than at L1. This may be explained by the difference in bone architecture at different levels of the ridge. The crestal region contains relatively more cortical bone and may resist deformation, whereas the mid-apical and apical regions contain more trabecular bone and may respond better to lateral compaction produced by densifying burs. This observation is clinically important because it indicates that osseodensification may not produce uniform expansion throughout the entire ridge, and clinicians should interpret crestal and deeper ridge changes separately.

Age and gender did not show a consistent statistically significant influence on peri-implant bone density or alveolar ridge width. This suggests that the observed improvements were mainly associated with the local effect of osseodensification and the baseline bone characteristics rather than demographic variables. However, this finding should be interpreted with caution because of the limited sample size.

The statistically significant increase in alveolar ridge width and peri-implant bone density observed in the present study supports the effectiveness of the osseodensification technique in D3 and D4 bone of the posterior maxilla. The preservation and compaction of autogenous bone during osteotomy preparation may contribute to increased peri-implant bone density and improved healing. These findings are supported by the statistically significant differences observed between the study time points and are consistent with the biological principles of osseodensification, which promotes bone preservation and compaction rather than bone excavation.

The present study has several strengths. It evaluated the effect of osseodensification in the clinically challenging D3 and D4 bone of the posterior maxilla, with serial CBCT assessments performed at preoperative, immediate postoperative, and four-month follow-up intervals. Furthermore, alveolar ridge width was assessed at three standardized levels (L1, L2, and L3), providing a comprehensive evaluation of ridge expansion and peri-implant bone density changes. To minimize methodological variability, all radiographic measurements were performed by a single examiner using a standardized protocol. In addition, the same implant system and dimensions (Dentis System, 4.0 × 10 mm) were used in all patients, thereby minimizing implant-related variability.

However, the present study also has certain limitations. The relatively small sample size and the absence of a conventional osteotomy control group limit the generalizability of the findings and preclude direct comparison with conventional drilling techniques. Furthermore, the increase in peri-implant bone density observed during the follow-up period may have been influenced not only by the osseodensification technique but also by the normal physiological bone healing process. In addition, peri-implant bone density was assessed using CBCT gray-scale values, which may not directly correspond to Hounsfield units obtained from medical CT, and the lack of calibration may introduce variability in density estimation. Therefore, the findings should be interpreted with this limitation in mind.

The study evaluated peri-implant bone density during the healing phase before functional loading; therefore, changes following prosthetic loading were not assessed. Furthermore, Implant Stability Quotient measurements were not included in the study protocol. These factors should be considered when interpreting the findings. Future randomized controlled clinical trials with larger sample sizes, longer follow-up periods, post-loading assessment, and additional clinical outcome measures are recommended.