Department of Pathology and Dentistry Clinic, School of Dentistry, Federal University of Piauí, Teresina, Brazil.
School of Dentistry, Federal University of Piauí, Teresina, Brazil.
Int J Paediatr Dent. 2018 Mar;28(2):198-206. doi: 10.1111/ipd.12327. Epub 2017 Aug 22.
The etiology of molar-incisor hypomineralization (MIH) remains unknown. Studies indicate that it is multifactorial, and that genetic and environmental factors are involved. Research with twins provides important subsidy to investigate the Influence of genetics and environmental factors that act during pregnancy on the etiology of alterations.
This cross-sectional study evaluated the agreement of molar incisor hypomineralization (MIH) between monozygotic and dizygotic twin pairs and the association with environmental factors.
The sample consisted of 167 pairs of twins (8-15 years old), 94 monozygotic and 73 dizygotic. The parents answered a questionnaire on sociodemographic data and pre-, peri-, and postnatal health. A dental examination was performed by two calibrated examiners (Kappa ≥0.88) for MIH diagnosis, following the criteria proposed by the European Academy of Pediatric Dentistry in 2003.
The prevalence of MIH was 29.3%. There was greater concordance of MIH between monozygotic twins for affected first molars and permanent incisors (P = 0.0012) and pairs of twins assessed (P = 0.0211). The presence of MIH was associated with family income between one and two wages (P = 0.009, prevalence ratio [PR] = 3.82, confidence interval [CI 95%] 1.40-10.44), above two wages (P = 0.007, PR = 4.60, 95% CI: 1.51-14.05), and gestational hemorrhage (P = 0.032, PR = 5.70, 95% CI: 1.16-28.14).
The greater concordance in the diagnosis of MIH among monozygotic twins indicates a genetic influence, although environmental factors, such as family income and hemorrhage during pregnancy, are also associated with the occurrence of MIH.
磨牙牙釉质发育不全（MIH）的病因尚不清楚。研究表明，它是多因素的，涉及遗传和环境因素。双胞胎的研究为调查遗传和环境因素对改变病因的影响提供了重要依据。
本横断面研究评估了单卵双生子和双卵双生子的磨牙牙釉质发育不全（MIH）的一致性，并与环境因素相关。
样本包括 167 对双胞胎（8-15 岁），94 对单卵双生子和 73 对双卵双生子。父母回答了一份关于社会人口统计学数据以及产前、围产期和产后健康的问卷。由两名经过校准的检查者（kappa≥0.88）进行牙科检查，以根据欧洲儿科牙科学会 2003 年提出的标准诊断 MIH。
MIH 的患病率为 29.3%。受影响的第一磨牙和恒切牙（P=0.0012）以及评估的双胞胎（P=0.0211）的单卵双生子之间 MIH 的一致性更高。MIH 的存在与家庭收入在 1 至 2 个工资之间有关（P=0.009，患病率比[PR]为 3.82，95%可信区间[CI 95%]为 1.40-10.44），高于 2 个工资（P=0.007，PR=4.60，95%CI：1.51-14.05）和妊娠期出血（P=0.032，PR=5.70，95%CI：1.16-28.14）。
单卵双生子 MIH 诊断的一致性更高表明遗传因素的影响，但环境因素，如家庭收入和妊娠期间出血，也与 MIH 的发生有关。
