Journal of Dental Medicine

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Statement of Problem: One of the important indications for the extraction of mandibular impacted third molar is to preserve the periodontal health of the adjacent second molar from the destructive effects of plaque accumulation, acute and chronic inflammation.
Aim: The purpose of this study was to determine the effect of mandibular third molar surgery on the PDL of the adjacent molar.
Materials and Methods: Thirty patients, referred to the department of maxillofacial surgery, Tehran University of Medical Sciences, were selected, based on the desirable conditions. They had no history of systemic diseases and their adjacent molar was healthy. Probing depth (PD) at seven points and attachment level (AL) at three points were measured preoperatively. Standardized periapical radiographics were taken regularly for all patients. All the above-mentioned procedures repeated after three months of surgery. Findings were analyzed by Paired t-test.
Results: A significant difference in probing depth (PD) was observed before and after surgery, meaning that probing depth decreased after mandibular third molar surgery. Attachment level was also decreased post operatively moreover. Intrabony defects (IBD) showed healing after surgery.
Conclusion: Considering the limitations of the present study, impacted third molar surgery is suggested to prevent periodontal problems of the adjacent molar.

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Background and Aims: Cone beam computed tomography (CBCT) produces high-quality data about diagnosis and periodontal treatment. To date, there is not enough research regarding periodontal bone measurement using CBCT. The aim of this study was to compare the accuracy of CBCT in measuring periodontal defects to that of intraoral radiography and probing methods.
Materials and Methods: Two-hundred and eighteen artificial osseous defects (buccal and lingual infrabony, interproximal, horizontal, crater, dehiscence and fenestration defects) were created on 13 mandibles of dry skulls. The mandibles were put into a plexiglass box full of water to simulate soft tissue. CBCT images, radiographic images taken with parallel technique and direct measurements using a WHO periodontal probe were recorded and compared to a standard reference (digital caliper). Inter and intra observe consistencies were assessed using Intra class correlation coefficient and pearson correlation.
Results: Inter and intra observer consistencies were high for CBCT and probing methods (ICC- Intra class correlation coefficient>88%), but moderate for intraoral radiography (ICC-Intra class correlation coefficient > 54%). There were not any significant differences between observers for all techniques (P>0/05). According to paired T-test analysis, mean difference for CBCT technique (0.01 mm) was lower than that for probing (0.04 mm) and radiography (0.62 mm). CBCT was able to measure all kinds of lesions, but radiography could not measure defects in the buccal and lingual sites.
Conclusion: All three modalities are useful for identifying periodontal defects. Compared to probing and radiography, the CBCT technique has the most accuracy in measuring periodontal defects.