Fagrell Tobias
Department of Pediatric Dentistry, Institute of Odontology, The Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden.
Swed Dent J Suppl. 2011(216):5, 11-83.
OVERALL AIM: The general objective of this thesis was to enhance the understanding of Molar Incisor Hypomineralization (MIH) in areas of the histological, chemical and mechanical properties of the hypomineralized enamel, objective and subjective clinical symptoms in relation to bacteria findings. Further, to estimate a time for onset of the disturbance and investigate possible etiological factors.
MATERIAL & METHODS: 22 teeth diagnosed with MIH were used in the histological and chemical studies. A number of analytical methods were used; Light microscopy, Polarized light microscopy, Scanning electron microscopy, X-ray microanalysis, Vickers hardness test and X-ray Micro Computed Tomography. Decalcified sections were stained with bacterial staining. An ozone device was tested for the ability to kill strains of oral bacteria. In collaboration with the prospective ABIS study, 17.000 individuals were examined and possible etiological causes of severe demarcated opacities were tested.
RESULTS & CONCLUSIONS: The hypomineralized enamel was mainly located in the buccal enamel of the teeth and had a high degree of porosity extending from enamel-dentin-junction with a distinct border to the normal cervical enamel. Teeth diagnosed MIH had lower hardness values in hypomineralized enamel and differences in the chemical composition. Bacteria were observed in the enamel and deep into the dentin. Ozone treatment for 20 seconds or more was effective to kill oral microorganisms. Significant relations were found between MIH in first molars and breast feeding more than 6 months, late introduction to gruel and infant formula (later than 6 months). The onset for the hypomineralized enamel was estimated to around 200 days from start of the enamel mineralization.
总体目标：本论文的总体目标是增进对磨牙釉质发育不全（MIH）的理解，包括釉质发育不全区域的组织学、化学和力学特性，与细菌发现相关的客观和主观临床症状。此外，估计病变发生的时间并调查可能的病因。
22颗诊断为MIH的牙齿用于组织学和化学研究。使用了多种分析方法；光学显微镜、偏光显微镜、扫描电子显微镜、X射线微分析、维氏硬度测试和X射线显微计算机断层扫描。脱钙切片用细菌染色法染色。测试了一种臭氧装置杀灭口腔细菌菌株的能力。与前瞻性ABIS研究合作，对17000人进行了检查，并测试了严重界限性牙釉质浑浊的可能病因。
釉质发育不全主要位于牙齿的颊侧釉质，具有高度的孔隙率，从釉质-牙本质交界处延伸至正常颈段釉质，边界清晰。诊断为MIH的牙齿在釉质发育不全区域的硬度值较低，化学成分也有差异。在釉质和牙本质深层观察到细菌。臭氧处理20秒或更长时间可有效杀灭口腔微生物。发现第一恒磨牙的MIH与母乳喂养超过6个月、辅食和婴儿配方奶引入较晚（晚于6个月）之间存在显著关联。釉质发育不全的发病时间估计在釉质矿化开始后约200天。
