26 November 2021

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Impacted mandibular third molars: Can they cause carious lesions and periodontal disease in adjacent teeth?

Lara Figini

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Impacted mandibular third molars (MTM) or in disodontiasis often cause various pathologies, such as pericoronitis, infections, caries of adjacent teeth, periodontitis, external root resorption and cyst / neoplastic alterations, as well as creating difficulties in prosthetic rehabilitation in many cases. and in orthodontic treatments or to give painful symptoms to the temporomandibular joint. However, the prophylactic surgical removal of asymptomatic impacted MTMs is still controversial, as there is no scientific or clinical consensus on which types of MTM should be removed for prophylactic purposes. Furthermore, in clinical practice, unfortunately, there is a lack of guidelines in this regard.

Materials and Methods
In a retrospective study, published in the November 2021 Journal of Periodontology, the authors investigated the effects that impacted mandibular thirds (MTMs) can have on themselves and adjacent teeth, providing evidence for prophylactic extraction of impacted MTMs. The authors reviewed panoramic radiographs of patients included in the study who referred to Guangzhou Medical University Affiliated Stomatology Hospital from April 2014 to May 2018 with the aim of investigating dental and periodontal carious lesions in TMJs and mandibular second molars. adjacent (MSM), investigating whether there was also a correlation between the severity of the lesions and the age of the patients.

Results
Of the 2650 impacted MTMs analyzed, 6.98% had carious lesions and 37.81% periodontal lesions, more than 24.63% of cases had dental carious lesions in the distal part of the adjacent MSMs and more than 35.30% lesions periodontal in the distal part of adjacent MSMs. 9.27%, 2.02%, 0.47% and 13.33% carious lesions and 48.81%, 17.31%, 5.19% and 10% periodontal lesions were observed in the mesial inclined MTM mandibular third molars. , horizontal, inverted and offset respectively. For adjacent mandibular second molars in 31.98%, 11.82%, 1.94% and 13.33%, distal carious lesions and distal periodontal lesions occurred in 45.74%, 16.95%, 2.91 % and 23.33% in cases of mesio-inclined, horizontal, inverted and disto-inclined third molars respectively. In mesio-tilted MTM third molars, severity of distal carious lesions and periodontal lesions of adjacent MSM sevenths was shown to be correlated with patient age (P <0.05).

Conclusions
From the data of this study, which need to be confirmed in other similar studies, it can be concluded that early prophylactic extraction of mesio-inclined MTM mandibular third molars and close monitoring of MTM mandibular third molars with horizontal / inverted impact and disto-inclined could prevent both carious lesions. that periodontal is borne by the third molars themselves and by the adjacent seventh molars.

For additional information: The association of mandibular third molar impaction with the dental and periodontal lesions in the adjacent second molars