Do wisdom teeth induce lower anterior teeth crowding? A systematic literature review.

OBJECTIVE: Individuals with dental crowding are the most frequent patients in the orthodontic practice.The purpose of this article is to find out if the lower third molars are the main reason of crowding in the lower dental arch. As well to find out other factors which can influence the lower incisors crowding. METHODS: The aim was to identify studies and reviews related to the effect of the lower third molars on the lower dental arch crowding. A literature survey was performed using Medline database. Used key words were lower third molar, influence of wisdom teeth, wisdom teeth and anterior crowding, lower dental arch changes. The articles from 1971 to 2011 related to topic were identified. Selected articles were published in dental journals in English. Full texts of the selected articles were analyzed. Articles about the dental crowding after orthodontic treatment were not included. All studies accomplished with human participants. RESULTS: It was found 223 articles but only 21 articles corresponded to selected criteria and were analyzed. This review is based on the investigations of 12 laboratory researchers, 4 clinical researches, 2 questionnaires and 3 literature reviews. CONCLUSION: The results are quite contradictory: some authors support the opinion that lower third molars cause teeth crowding, the others confirm conversy. Exist other factors affecting the mandibular incisors crowding: dental (teeth crown size, dental arch length loss, poor periodontal status and primary teeth loss), skeletal (growth of the jaws and malocclusion) and general (age and gender).

Lower dental arch changes after bilateral third molar removal.

OBJECTIVE: To evaluate the changes in lower dental arch after bilateral lower third molars removal. MATERIAL AND METHODS: The study group consisted of 30 non-orthodontic patients (mean age 25,5 years, refered for bilateral lower third molars removal. Orthopantomograms and dental casts were made before and 6-8 months after surgical removal of lower third molars. Transversal lower arch widths between lower canines and second premolars and lower arch total tooth size-arch lenght discrepancy were evaluated on dental casts. The angulation of lower second premolars, first and second molars was measured in horizontal and mandibular planes on orthopantomograms. RESULTS: No significant difference of inter-canine and inter-premolar transversal width was noticed. No significant changes were observed in total tooth-size lenght discrepancy, except in S1 segment consisted of first and second premolar and the canine on the right quadrant of the lower dental arch. The angulation of second premolars and first molars did not show any significant changes, however there were statistically significant changes between angulation of lower second molars on both sides. CONCLUSIONS: After bilateral removal of lower third molars, lower second molars awhile showed a tendency to move backwards, but no obvious relationship between the third molar and anterior crowding was observed. Whereas the observation time is short and the patient's age is young and it can not be concluded that lower third molars cause the changes in the dental arch.