Title:  Relationship between pulpal involvement of primary molars and eruption pattern of premolars

Abstract:  Aim This study’s aim was to investigate the relationship between deep caries, with pulp necrosis of primary molars, and the pattern of eruption of the corresponding premolars. Methods A total of 126 children were followed up to the completion of premolar eruption over an 8-year period. Criteria for case selection included arch length adequacy and absence of abnormally large teeth. Primary molars were classified as test teeth if affected by deep caries; otherwise they were classified as control teeth. Eruption of corresponding premolars was classified as either centric or ectopic in relation to the area of eruption on the alveolar ridge. Results A total of 682 premolar eruptions were examined. Of these 73 (10.7%) eruptions of premolars were ectopic; 308 (45.2%) primary molars presented with deep caries and pulp necrosis. Some 61 (83.6%) out of the 73 ectopic eruptions occurred in association with pulp necrosis of the primary molars. A chi-square test was used to study the relationship between deep caries of primary molars and ectopic eruption of premolars, separately for upper and lower arches and for first and second premolars. A significant association was found for both first (p<0.01) and second (p<0.05) mandibular premolars, and for maxillary first premolars (p<0.0001). No significant association was assessed for maxillary second premolars. Conclusion Deep caries with pulp involvement of primary molars appears to be a factor associated with deviations of the eruption pattern for corresponding premolars. Clinical consequences may include the need for orthodontic treatment and periodontal concerns regarding the amount of keratinized gingiva of ectopically erupting premolars.