片側の乳歯と永久歯の多発性無歯症とその可能な対処法

Agenesis of multiple primary and permanent teeth unilaterally and its possible management.

抄録

寡歯症とは、多数の歯（6本以上）の無茎症である。乳歯列と永久歯列の歯牙の無茎症は稀であり、歯科文献に報告されているのはごくわずかである。先天性歯牙欠如症の病因は不明であるが、遺伝的傾向、代謝異常、外傷、感染、放射線、特発性などのいくつかの要因があることが分かっている。文献によると、発生頻度の高い順に第3大臼歯、上顎側切歯、下顎中切歯・側切歯、下顎第2小臼歯の先天性欠如が多く報告されています。男性の方が女性より多い。上顎の乳歯は下顎の乳歯に比べ、より頻繁に無歯症の影響を受けていることが判明しています。欠損は片側または両側に認められ、永久歯列でも同様の現象が起こりやすいと報告されている。先天性無歯顎症の場合、歯槽突起の成長障害、下顔面高さの減少、言語障害、深咬合、アンキロロガーゼによる舌の運動制限、患側顔面の非対称などが臨床的特徴として明らかである。上顎第2・3大臼歯の欠如を伴う下顎骨全周の乳歯・永久歯完全非発生例はこれまで報告がない。今回，数本の乳歯欠損とその完全欠如による発語困難を主訴に来院した10歳児において，右下顎四分円内に片側10本以上の乳歯・永久歯の完全欠如という稀な症例を経験したので報告する．治療方針は、審美性と機能性を改善するために、様々な歯列矯正と修復処置を行った。矯正治療では、機能的に適合した咬合を得るために狭い上顎弓を拡大し、将来の歯並びのためのスペースを確保し、舌を収容し発声を矯正するために上顎右側後頭部を隆起させ保護する処置を行いました。修復処置では、欠損歯の修復、審美性の改善、下唇の舌側支持、右上顎稜の下方成長防止、これらの歯の上萌出防止のための一時的措置として、取り外し可能な部分義歯を作製しました。

Oligodontia is the agenesis of numerous teeth (more than six teeth). Agenesis of teeth in primary and permanent dentition is a rare incidence and very few are reported in the dental literature. Although the etiology of congenital agenesis of teeth is unclear, several factors such as a tendency toward genetic predilection, metabolic disorders, trauma, infection, radiation or idiopathic reasons are found to be responsible. Available literature reports agenesis most often of third molars, maxillary lateral incisors, mandibular central and lateral incisors, and mandibular second premolars in decreasing order of frequency of occurrence. Males are more often affected than females. Maxillary primary teeth are more often found affected by agenesis than mandibular primary teeth. Available literature reports missing teeth to be found unilaterally or orbilaterally with a predisposition toward a similar phenomenon occurring in the permanent dentition. In congenital agenesis impaired growth of the alveolar process, reduced lower facial height, speech impairment, deep bite, restriction in the movement of the tongue due to ankyloglossia, asymmetry of the affected side of the face are clinical features evident. There has been no report of complete agenesis of primary and permanent teeth in a whole mandibular quadrant in conjunction with the absence of maxillary second and third molars on the affected side. Here, we report an incidence of a rare occurrence of complete agenesis of more than 10 primary and permanent teeth, unilaterally, in the right mandibular quadrant, in a child of 10 years presenting with a chief complaint of several missing primary teeth and difficulty in speech due to its complete absence. Treatment strategies included various orthodontic and restorative procedures to improve esthetics and function. The orthodontic procedures involved expansion of the narrow maxillary arch to obtain a functionally adapted occlusion and creation of space for future alignment, and uprighting and protecting maxillary right posteriors to accommodate the tongue and rectify speech. Restorative procedures involved fabrication of a removable partial denture as a temporary measure to restore missing teeth, improve esthetics, give lingual support to the lower lip, prevent further downward growth of the right maxillary ridge and to prevent supra eruption of these teeth.