Delayed eruption of first molars due to immature tooth formation: Report of five cases

Five cases of delayed eruption of the first molars due to immature tooth formation are presented. Three cases involved a teeth in a single quadrant, two of which were the maxillary left region while the other was in the maxillary right region. Both the maxillary left and right regions were affected in one case, and all four molar regions were affected in another case. Dental age was calculated by evaluating the tooth developmental stage in each case, and was compared with chronological age ( CA). The mean dental age, excluding the affected molar region ( MD), was compared with the dental age of the affected tooth (DA). The CA was more than 1 SD older than the MD in four cases. When we considered the affected molars to be first permanent molars, DA was 1.51-2.43 years younger than MD in all five cases, while DA was approximately 1.07-2.39 years older than MD when the affected molars were considered as second permanent molars. These results indicated that the developmental stages of the affected molars were between that of the first and second molars, and were estimated to have emerged into oral cavity at an age between 9 and 10 years old.