Changes in bone mass in rat mandibles after tooth extraction.

Area of Science:

• Oral and Maxillofacial Surgery
• Bone Biology
• Experimental Pathology

Background:

• Trabecular bone mass in the jaw is influenced by mechanical loading.
• Understanding the effects of reduced occlusal forces on jawbone integrity is crucial for dental implantology and oral health.
• Previous research has explored bone remodeling but specific impacts of localized bite force reduction require further investigation.

Purpose of the Study:

• To investigate the effects of unilateral upper molar extraction on mandibular trabecular bone mass in rats.
• To quantify changes in bone area percentage following a reduction in local bite force.
• To establish a correlation between decreased mechanical stimulation and bone density alterations in the jaw.

Main Methods:

• An experimental study was conducted on 32 SPF Wistar rats (16 weeks old).
• Upper right molars were extracted in the experimental group; control group received no extraction.
• Mandibular bone mass was assessed using microradiography and electronic point counting on ground sections after 16 weeks.

Main Results:

• No significant difference in bone mass was observed between the left and right sides in the control group (P > 0.50).
• A statistically significant difference in bone mass was found between the left and right sides in the experimental group (P ≈ 0.0001).
• The right side of the mandible (ipsilateral to extraction) showed a significantly lower mean bone mass compared to the left side.

Conclusions:

• Local reduction in bite force due to molar extraction causes significant osteoporotic changes in the trabecular bone of the jaw.
• Mechanical loading is a critical factor in maintaining jawbone density.
• The findings suggest that loss of occlusal function can lead to localized bone resorption in the mandible.