Ectopic eruption of the maxillary first permanent molar

Ectopic eruption of the maxillary first permanent molar is an eruption disturbance. This article discusses current literature views on diagnosis, prevalence, aetiology and treatment of this disturbance. It is a relatively uncommon disturbance and its aetiology remains unclear. A combination of extraction of the maxillary second primary molar and cervical headgear treatment seems the treatment of choice, although this treatment option is successful in only 70% of cases. More research has to be conducted to compare the effectiveness of treatment options.     

Ectopic eruption of the first permanent molar.

It is possible to resolve an ectopic eruption with the placement of a steel crown on the second primary molar. This article is a review of the recent literature and the presentation of three cases showing the resolution of ectopic molars using steel crowns.     

Ectopic eruption of the maxillary second molar: Predictive factors

Objective:The purpose of this study was to investigate the diagnostic aspects, contributing conditions, and predictive key factors associated with ectopic eruption of maxillary second molars.Material and Methods:This retrospective study evaluated the study models, lateral cephalographs, and panoramic radiographs of 40 adult subjects (20 men, 20 women) with bilateral ectopic eruption and 40 subjects (20 men, 20 women) with normal eruption of the maxillary second molars. Studied variables were analyzed statistically by independent t-tests, univariate and multivariate logistic regression analysis, followed by receiver-operating characteristic analysis.Results:Tooth widths of bilateral lateral incisors, canines, and premolars were wider in the ectopic group, which resulted in greater arch lengths. The ANB angle and maxillary tuberosity distance (PTV-M1, PTV-M2) were smaller in the ectopic group. The long axes of the maxillary molars showed significant distal inclination in the ectopic group. The multivariate logistic regression analysis showed that three key factors—arch length, ANB angle, and PTV-M1 distance—were significantly associated with ectopic eruption of the second molars. The area under the curve (AUC) was the largest for the combination of the three key factors with an AUC greater than 0.75. PTV-M1 alone was the single factor that showed the strongest association with ectopic eruption (AUC = 0.7363).Conclusions:An increase in arch length, decrease in ANB angle, and decrease in maxillary tuberosity distance to the distal aspect of the maxillary first molar (PTV-M1) were the most predictive factors associated with ectopic eruption of maxillary second molars.     

Ectopic eruption of the maxillary permanent first molar: the effect of increased mesial angulation on arch length

Fifty-four cases of ectopically erupted maxillary permanent first molars were studied with a method using the measurements obtained from photographs of the study casts. The amount of relative loss of anteroposterior arch length of the right and left sides was shown to correlate with the increased mesial angulation of the maxillary permanent first molar. The bilateral ectopic group has a significantly larger mesial angulation of the permanent first molar on a maxilla with shorter anteroposterior arch length. The relative loss of arch length with ectopic eruption of the permanent first molar limits the use of unilateral appliances for treatment. The use of an appliance with bilateral arch support seems preferable.     

弹弓式磨牙远移器治疗上颌第一恒磨牙异位萌出

目的评价使用弹弓式磨牙远移器治疗第一恒磨牙异位萌出的临床效果。方法选择替牙期不可逆性第一恒磨牙异位萌出患者8例,男3例,女5例,年龄6.8~9.5岁,平均8.6岁。所有病例均存在不同程度的第二乳磨牙远中根吸收。采用弹弓式磨牙远移器标准型或简化型矫治器治疗,推第一恒磨牙向远中移动,使第一恒磨牙与第二乳磨牙远中面脱离接触并最终萌出到正常位置。结果所有病例第一恒磨牙牙冠均向远中移动并竖直,与第二乳磨牙脱离接触。治疗时间1.5~4.0个月,平均2.2个月。结论弹弓式磨牙远移器是治疗第一恒磨牙异位萌出的有效方法。     

Treatment of children with ectopic eruption of the maxillary first permanent molar by cervical traction

The sequelae of extraction of the second deciduous molar due to irreversible ectopic eruption of the maxillary first permanent molar are mesial tipping of the permanent molar and subsequent space loss. The purpose of this study was to evaluate the effects of early treatment with the Kloehn type of cervical headgear. Forty-six children with ectopic eruption were treated. The mean age at the start of treatment was 8.3 years (range, 6.5 to 9.9 years) and the mean treatment time was 0.8 year (range, 0.5 to 1.0 year). Nineteen variables from orthopantomograms, lateral head films, and dental casts were analyzed by one-way analysis of variance. The registrations were made at the start of treatment, at the end of treatment, and 1 year posttreatment. The treatment resulted in distal tipping of the first permanent molar to a good occlusion in all children. The s-n-ss angle decreased during treatment in all children, and a mean proclination of the maxillary incisors of 3 degrees was registered. Proclination was independent of the type of occlusion and was unchanged 1 year posttreatment. The ss-n-sm angle was also reduced during treatment and was unchanged 1 year posttreatment. The most favorable time for treatment seems to be when the second premolar is close to eruption or erupting at the end of the treatment period. Because of the risk of inhibited sagittal growth of the maxilla with this type of treatment, careful cephalometric evaluation is considered important before the start of treatment.     

Ectopic eruption of the maxillary central permanent incisors and mandibular first permanent molars: report of an unusual case.

Ectopic eruption is a disturbance in which the tooth does not follow its usual course. Among its more important etiologic factors are macrodontism, shortened arch length, posterior positioning of the maxilla, atypical eruption angle, and genetic factors. This article reports a rare case of ectopic eruption of 4 permanent teeth, maxillary central incisors and mandibular first molars, in a child aged 7 years and 11 months, in which the treatment consisted of extracting the maxillary primary central incisors and making an orthodontic intervention on the mandibular arch. A bilateral fixed appliance containing 2 hooks with loops, 1 buccal and the other lingual, was placed on the mandibular primary first molars. The hooks were activated in a niche made of light-curing resin on the occlusal surface of the mandibular permanent molars, to bring about the distal drift of these teeth. After 6 months, complete eruption of the mandibular permanent molars occurred, and a slight displacement of the maxillary permanent central incisors toward the median line was noted. The importance of early, adequate treatment is discussed.     

Ectopic eruption of a maxillary third molar tooth in the maxillary sinus: a case report

Ectopic eruption of teeth into regions other than the oral cavity is rare although there have been reports of teeth in the nasal septum, mandibular condyle, coronoid process, palate, chin, and maxillary sinus. Occasionally, a tooth may erupt in the maxillary sinus and present with local sinonasal symptoms attributed to chronic sinusitis. We present a case of an ectopic maxillary third molar tooth that caused chronic sinusitis in the maxillary sinus.     

Ectopic eruption of maxillary first permanent molars and association with other tooth and developmental disturbances.

The associations between tooth and eruption disturbances in four groups of children selected primarily with only one diagnosed eruption or developmental disturbance in each group was analysed. Ninety-two children were primarily diagnosed with ectopic eruption of maxillary first permanent molars, 93 children with infra-occlusion and ankylosis of primary molars, 91 children with ectopic eruption of maxillary canines, and 97 children with aplasia of premolars. Of the children studied 69-79 per cent had only a single one of the four disturbances studied. In 18-28 per cent there was one additional disturbance and in 2-3 per cent two additional disturbances. From chi square contingency tests, it was found that infra-occlusion of primary molars and aplasia of premolars exhibited a higher prevalence in both directions compared to the expected population prevalence. Ectopic eruption of maxillary canines showed a significantly higher prevalence than expected in all the other three groups. Our interpretation is that these results support the hypothesis of a common, presumably hereditary, aetiology. Thus, the four conditions studied would be different manifestations of one syndrome, each manifestation having an incomplete penetrance. With closer follow-up of the maxillary canines during the eruption period in children with some of the other three disturbances, prophylactic, or early interceptive measures may be taken and complicated orthodontic treatment be reduced or avoided.     

Failure of eruption of first permanent molar teeth: a diagnostic challenge

Ankylosis, mechanical and primary failure of eruption of molar teeth are rare and often difficult to distinguish between. All may have significant repercussions on the occlusion and successful management may involve invasive procedures. We present a case where an initial presentation characteristic of mechanical failure of eruption (ankylosis) of a first permanent molar tooth was excluded following a period of monitoring. Subsequent relief of crowding using a removable and then sectional fixed orthodontic appliance allowed spontaneous eruption of the tooth obviating the need for surgical intervention. This case highlights the utilisation of conservative treatment options until a diagnosis was confirmed to minimise the risk of iatrogenic damage and unnecessary treatment.