Effects of hypodontia on craniofacial structures and mandibular growth pattern

Introduction This study was performed to examine craniofacial structures in persons with hypodontia and to reveal any differences, that may occur, when agenetic teeth are only found in the maxilla, the mandible or in both jaws. The groups consistent of 50 children (33 girls, 17 boys) aged between 9 and 13.5 years were analyzed and assigned to three subgroups. Group 1= upper jaw hypodontia. Group 2= lower jaw hypodontia. Group 3= hypodontia in both jaws. Material and methods Eleven angular and three index measurements from lateral encephalographs and two linear measurements from dental blaster casts were calculated. All data was statistically analyzed, parameters with p<5% were investigated for each subgroup respectively. Results In comparison with standards the study group showed bimaxillary retrognathism and a reduction of the lower anterior facial height. Moreover both overbite and overjet significantly increased. Other values laid within the normal ranges. Evaluating results of the subgroups, differences in the means of SNA, SNB and overjet between the groups were observed. Analysis of the mandibular growth pattern revealed, that neither vertical nor horizontal patterns are dominant in hypodontia patients. Conclusions In certain dentofacial parameters differences between persons with hypodontia and such with full dentition exist. According to our findings agenetic teeth may have a negative influence on the saggital development of a jaw and the lower face and may be responsible for increased overbites. This should receive attention in orthodontic treatment of hypodontia patients

DİŞ YAPISI İLE İLİŞKİLİ GENETİK MALFORMASYONLAR [The Genetic Malformations Related with Tooth Structure]

ÖZET Son yıllarda genetik alanındaki ilerlemeler, diş gelişimi ile ilişkili genetik geçişe sahip anomaliler ve gen mutasyonlarının daha iyi anlaşılabilmesine olanak sağlamaktadır. Diş oluşumu sırasında belirli zamanlarda sentezlenen defektif genlere bağlı olarak, çeşitli diş malformasyonları görülmektedir. Diş gelişiminin kuron oluşum safhasında, ameloblastlar ve odontoblastlar tarafından sentezlenen genlerin, mine ve dentin yapı anomalileri ile ilişkili olduğu ortaya konulmuştur. Diş gelişimi sırasında ortaya çıkan defektler, tek (izole) olarak veya diğer organ ve dokularla birlikte (bir sendromla ilişkili olarak) meydana gelebilmektedir. Kalıtsal diş patolojileri ve normal diş gelişimi arasındaki ilişkinin anlaşılması, hastaların doğru ve etkili bir şekilde tedavi edilmesini ve dişsel anomalileri içeren bazı sendromların daha erken teşhis edilmesini sağlayacaktır. ABSTRACT Nowadays, improvement that has occurred about genetic studies allows to better understanding of genetic abnormalities and gene mutations associated with tooth development. Depending on the defective genes which are expressed during tooth formation at specific times, various tooth malformations can be seen. The genes expressed from odontoblasts/ameloblasts during crown formation, were presented to be associated with developmental defects of enamel and dentin. The defects in tooth formation process can be seen with other tissues, organs (related with a syndrome) or alone (isolated). Understanding the relationship between normal tooth formation and hereditary tooth pathologies will provide the early diagnosis of syndromes including tooth anomalies and effective treatment of those patients