CBCT: bone density varies mainly between anterior and posterior sectors

Assessment of bone density by CBCT: a prerequisite for implant success

The clinical success of a dental implant relies on two fundamental pillars: primary stability and the quality of osseointegration, both of which are closely correlated with the bone density of the recipient site. Given the high prevalence of oral pathologies leading to edentulism, preoperative planning requires an objective and precise evaluation to adapt drilling protocols. Although Cone Beam imaging (CBCT) has become the standard for three-dimensional analysis, the variability of densities according to anatomical sectors remains a crucial data point to quantify in order to secure the surgical procedure.

This observational study, conducted by García Linares and Almerco Eulogio, aimed to determine the differences in bone density in the edentulous ridges of the maxilla and mandible. By analyzing 150 tomographic examinations in adult patients aged 40 to 60, the authors sought to identify regional disparities (anterior versus posterior) expressed in Hounsfield units (HU). The study tests the hypothesis that bone topography induces significant density variations, directly influencing the implant prognosis and requiring a sectorized diagnostic approach.

Methodology: Densitometric analysis by CBCT

This observational, descriptive, and cross-sectional retrospective study evaluated the bone density of edentulous ridges using cone beam computed tomography (CBCT). The objective was to provide an objective preoperative assessment for implant diagnosis.

The protocol was based on the following parameters:

• Sample: 150 tomographic examinations selected by a non-probabilistic convenience method.
• Population: Adult patients aged 40 to 60 years.
• Measurement units: Density was quantified in Hounsfield Units (HU) from CBCT data.
• Anatomical segmentation: Measurements were distributed between the maxilla and the mandible, with a systematic distinction between the anterior and posterior regions.

Researchers classified the results into three defined density ranges: low density (151-350 HU), medium density (351-850 HU), and high density (851-1250 HU). Statistical analysis compared these values according to patient gender and precise location on the edentulous alveolar ridges.

Bone density analysis: topography takes precedence over the arch

The study conducted on 150 tomographic examinations (CBCT) in patients aged 40 to 60 years shows that the majority of edentulous ridges fall within a medium density range, between 351 and 850 Hounsfield Units (HU). While the overall distinction between the maxilla and the mandible does not reveal major disparities, the analysis segmented by region (anterior versus posterior) highlights statistically significant differences.

Clinical observations from this retrospective series highlight a marked heterogeneity depending on the location:

• In the maxilla: A decreasing density gradient is observed. The anterior region maintains medium density, while the posterior region is dominated by low density (151-350 HU), representing a challenge for primary stability.
• In the mandible: Density is significantly higher, with a predominance of highly mineralized tissues (851-1250 HU) in the symphyseal sector and a stable average density in the posterior zone.

Comparative analysis by gender shows a slightly higher bone density in men, with an average of 663 HU compared to 655 HU in women. Although this 8 HU difference is quantifiable, it remains clinically less impactful than the regional variations observed between the anterior and posterior sectors.

Analysis of density by region and clinical implications

The results of this study confirm a marked topographical variability that must dictate the drilling protocol. The predominance of medium density (351-850 HU) in the anterior maxilla (39.6%) contrasts with the posterior region where low density (151-350 HU) concerns 36% of cases. For the implantologist, the posterior maxillary sector remains the most critical area for achieving satisfactory primary stability without specific bone grafting or drilling protocols.

Conversely, the mandible presents a higher resistance profile. The study shows that the anterior region is dominated by high density (851-1250 HU) in 37.3% of subjects. This data is crucial to avoid the risks of bone overheating during drilling. The slight superiority in density observed in men (663 HU versus 655 HU) remains clinically less determining than the anatomical location itself.

Cette étude comporte toutefois des limites : son caractère rétrospectif et son échantillonnage de convenance restreignent la généralisation stricte des résultats. De plus, bien que le CBCT soit un outil performant, la conversion en Unités Hounsfield peut varier selon les constructeurs, nécessitant une calibration logicielle rigoureuse pour le praticien.

Summary of results

This observational study of 150 CBCTs demonstrates that while average bone density (351-850 HU) predominates overall, major regional variations remain: the anterior mandibular region shows high density (851-1250 HU) in 37.3% of cases, while the posterior maxilla presents low density (151-350 HU) in 36% of cases. A minor difference was noted between genders, with an average of 663 HU in men versus 655 HU in women.

In concrete terms, for the practitioner:

• Individualize the drilling protocol in the posterior maxilla: Given the 36% prevalence of low density, the objective evaluation of Hounsfield units (HU) is crucial to adapt the implant design and promote primary stability.
• Manage high-density bone in the symphyseal area: With more than a third of anterior mandibular sites exceeding 850 HU, plan for a limited under-drilling protocol and new drills to avoid cortical overheating.
• Put the impact of gender into perspective: Since the density gap between men and women is clinically negligible (8 HU difference), your surgical strategy should prioritize anatomical location rather than the patient's gender.

Information intended for healthcare professionals. This content may contain errors or truncated summaries. We recommend always verifying with the original source article. Delynov disclaims any responsibility regarding the use of this information. This document is not intended for patients or the general public.