Secondary retention of permanent molars. I. Clinical, radiologic and histologic characterization

The clinical, radiographical and histological aspects of secondary retention in permanent molars were studied in a group of 53 patients with 81 secondarily retained permanent molars. First molars turned out to be affected most frequently. The mean infraocclusion at the patients' first visit was 4.3 mm. After six months, infraocclusion had increased in adolescents. It seemed to be stable in adults. Tilting of adjacent teeth was observed in 39 cases of secondary retention. A solid, clear percussion sound and a partial absence of the periodontal ligament space on radiographs was only noted in less than 20% of the affected molars, while histological examination of 38 removed molars revealed that local areas of ankylosis were present in all cases. During a follow-up period of four years, six new cases of secondary retention were observed in the same population.</p

Secondary retention of permanent molars. II. Therapy

The efficacy of 5 treatment modalities for secondary retention of permanent molars was evaluated in 62 patients with 92 affected molars. The results showed that a prosthetic build up is a proper treatment if secondary retention develops late in or after the growth spurt. In these cases the extent of infraocclusion is slight and relatively stable. If secondary retention starts before the growth spurt, immediate removal of the retained molar followed by orthodontic treatment to close the diastema gives maximal success. When secondary retention develops during the growth spurt, the tooth affected has to be observed at six monthly intervals. In such cases, no active treatment is indicated if the extent of infraocclusion is minor and stable. In all other cases the affected molar should be removed, followed by orthodontic closure of the diastema.</p

Secondary retention of permanent molars. I. Clinical, radiologic and histologic characterization

The clinical, radiographical and histological aspects of secondary retention in permanent molars were studied in a group of 53 patients with 81 secondarily retained permanent molars. First molars turned out to be affected most frequently. The mean infraocclusion at the patients' first visit was 4.3 mm. After six months, infraocclusion had increased in adolescents. It seemed to be stable in adults. Tilting of adjacent teeth was observed in 39 cases of secondary retention. A solid, clear percussion sound and a partial absence of the periodontal ligament space on radiographs was only noted in less than 20% of the affected molars, while histological examination of 38 removed molars revealed that local areas of ankylosis were present in all cases. During a follow-up period of four years, six new cases of secondary retention were observed in the same population.</p