PEDIATRIC DENTISTRY V 39 / NO 7 NOV / DEC 17 O CROSS-SECTIONAL STUDY Are Hypomineralized Primary Molars and Canines Associated with Molar-Incisor Hypomineralization? Maria Jose da Silva Figueiredo Sé, DDS, MS1 • Ana Paula Dias Ribeiro, DDS, MS, PhD2 • Lourdes Aparecida Martins dos Santos-Pinto, DDS, MS, PhD3 Rita de Cassia Loiola Cordeiro, DDS, MS, PhD4 • Renata Nunes Cabral, DDS, MS5 • Soraya Coelho Leal, DDS, MS, PhD66 Abstract: Purpose: The purpose of this study was to evaluate the prevalence of and relationship between hypomineralized second primary molars (HSPM) and hypomineralized primary canines (HPC) with molar-incisor hypomineralization (MIH) in 1,963 schoolchildren. Methods: The Europe- an Academy of Paediatric Dentistry (EAPD) criterion was used for scoring HSPM/HPC and MIH. Only children with four permanent first molars and eight incisors were considered in calculating MIH prevalence (n equals 858); for HSPM/HPC prevalence, only children with four primary second molars (n equals 1,590) and four primary canines (n equals 1,442) were considered. To evaluate the relationship between MIH/HSPM, only children meeting both criteria cited were considered (n equals 534), as was true of MIH/HPC (n equals 408) and HSPM/HPC (n equals 360; chi-square test and logistic regression). Results: The prevalence of MIH was 14.69 percent (126 of 858 children). For HSPM and HPC, the prevalence was 6.48 percent (103 of 1,592) and 2.22 percent (32 of 1,442), respectively. A significant relationship was observed between MIH and both HSPM/HPC (P<0.001). The odds ratio for MIH based on HSPM was 6.31 (95 percent confidence interval [CI] equals 2.59 to 15.13) and for HPC was 6.02 (95 percent CI equals 1.08 to 33.05). Conclusion: The results led to the conclusion that both hypomineralized second primary molars and hypomin- eralized primary canines are associated with molar-incisor hypomineralization, because children with HSPM/HPC are six times more likely to develop MIH. (Pediatr Dent 2017;39(7):445-9) Received May 2, 2017 | Last Revision July 17, 2017 | Accepted July 18, 2017 KEYWORDS: TOOTH DEMINERALIZATION, CHILD, ORAL HEALTH, DECIDUOUS TOOTH Molar-incisor hypomineralization (MIH) is defined as a devel- as MIH is diagnosed, children should be placed under a strict opmental enamel defect that affects at least one permanent first preventive program to avoid cavity development in any post- molar. Affected anterior teeth might also be observed.1 MIH eruptive enamel and the necessity for more complex restorative prevalence varies according to the population studied, ranging procedures. Therefore, if the clinical characteristics of the pri- from very low values (2.5 percent) in China2 to a prevalence mary dentition could predict the occurrence of MIH in the higher than 40 percent in Australia3 and Brazil.4 Such differ- permanent dentition, the dentist might be able to control recall ences cannot be explained only by differences in the population intervals and advise parents of the importance of seeing the studied; they are also affected by the lack of standardization in child as soon as the permanent first molar erupts. the research protocols.5 The prevalence of hypomineralized second primary molars MIH is characterized by demarcated opacities that vary (HSPM) shows a great variation ranging from zero percent12 to from white to a brownish color and which may progress to a 21.8 percent13 and an association with MIH.14,15 However, most posteruptive enamel breakdown.6 In the most severely affected studies were conducted in Europe, and there is no information individuals, dentin will be exposed. Histologically, the MIH about prevalence of MIH in primary teeth in children from opacity is more porous than sound enamel7 because of its lower North or South America. Moreover, whether the presence of mineral density, and porosity increases from white to brown demarcated opacities in the primary canines is also associated according to the opacity color.8 Clinically, this porosity makes with MIH is unknown, as the studies available report only on MIH opacities more prone to breakdown; also, the treatment primary second molars. is more challenging, because the porous enamel is a barrier to Therefore, the purposes of this study were to: (1) determine optimal bonding to adhesive materials.9 To make treatment even the prevalence of hypomineralized second primary molars and more complicated, hypersensitivity is a frequent complaint of hypomineralized primary canines (HPC); and (2) investigate patients affected by MIH.1 A subclinical, but constant, pulp whether an association existed between their occurrence and inflammation is present under the opaque area10; because of the occurrence of molar-incisor hypomineralization in a group that, pain control using local anesthesia might fail. of Brazilian schoolchildren. Children who are affected by MIH receive more invasive treatments than those who are not affected.11 Therefore, as soon Methods This study was approved by the Research Ethics Committee of the Faculty of Health Science of the University of Brasília, Drs. 1 Sé and 5Cabral are PhD students and 6Dr. Leal is a full professor, Department of Brasília, Brazil and authorized by the Department of Education Dentistry, Faculty of Health Sciences, University of Brasília, Campus Darcy Ribeiro, Asa of the local government. 2 Norte, Brasilia, Brazil; Dr. Ribeiro is a clinical assistant professor, Department of Re- A cross-sectional epidemiological study was carried out storative Dental Sciences, College of Dentistry, University of Florida, Gainesville, Fla., USA; and Drs. 3Santos-Pinto and 4Cordeiro are full professors, Department of Pediatric among six- to 11-year-olds from all six public schools located in Dentistry and Orthodontics, Araraquara School of Dentistry, Universidade Estadual a suburban area of Brazil’s Federal District (n equals 1,963). Paulista, Araraquara, São Paulo, Brazil. Children and their parents were invited to participate, and Correspond with Dr. Leal at [email protected] all those who signed the informed consent were included in HYPOMINERALIZED PRIMARY AND PERMANENT DENTITION 445 PEDIATRIC DENTISTRY V 39 / NO 7 NOV / DEC 17 the survey. Children who did not allow the examination were Data were analyzed using Stata 13.1 software (Stata, College excluded. Station, Texas, USA). Different numbers of children were used The socioeconomic status of the sample was considered for calculations as follows: for MIH prevalence, a total of 858 similar, since all participants resided in the same area and lived children were included based on the presence of all permanent similar life styles. All children had access to fluoridated water first molars and eight incisors; for HSPM prevalence and HPC, (0.7 ppm). only children with four primary second molars (n equals 1,590) Three examiners, all dentists, were trained and calibrated and four primary canines were considered (n equals 1,442). For on (1) the Caries Assessment Spectrum and Treatment (CAST) the association between MIH/HSPM and MIH/HPC, children instrument16-18 to register carious lesions; and (2) European had to present both conditions, totaling 534 and 408 included Academy of Paediatric Dentistry (EAPD) criterion1 to record children, respectively. In addition, children were grouped ac- MIH. The training sessions, conducted by two experts, com- cording to MIH/HSPM/HPC severity, as previously described. prised a theoretical explanation of both criteria (two hours for Statistical analysis was performed using the chi-square test and the CAST instrument and three hours for the EAPD criterion), logistic regression (odds ratio). followed by a discussion of: (1) a series of images containing different stages of carious lesions; and (2) teeth affected by MIH Results and other developmental enamel defects with different cate- Sample descriptive analysis. Of the 858 children with all perma- gories of severity. The severity was rated within three categories, nent first molars and eight incisors, 51.57 percent were girls and according to Leppaniemi et al.19: (1) mild (opacities without 48.43 percent were boys, with a mean age of 9.6±1.21 (SD) posteruptive enamel breakdown); (2) moderate (opacities with years. For this group, the prevalence for MIH was 14.69 per- posteruptive breakdown [PEB] limited to enamel); and (3) cent (126 children of 858). severe (PEB with dentin involvement, atypical restorations, and For HSPM, the sex distribution was 53 percent boys and tooth extraction due to MIH). PEBs were defined as enamel 47 percent girls, with a mean age of 8.11±1.29 (SD) years. The breakdown that occurred due to the severe porosity of the prevalence was 6.48 percent (103 of 1,590). For HPC, the sam- hypomineralized opaque areas that fracture when subjected to ple was composed of 55 percent boys and 45 percent girls, with masticatory forces, resulting in unprotected enamel/dentin.20 a mean age of 7.95±1.19 (SD) years; its prevalence was 2.22 After the visual training, for the CAST instrument, a percent (32 of 1,442). In considering the unit tooth, the pre- set of extracted teeth was examined, and the codes were dis- valence was reduced for all variables to 3.99, 2.19, and 0.69 for cussed. Afterward, in two separate clinical sessions, 10 children MIH, HSPM, and HPC, respectively (Table 2). in the same age groups as those in the survey, but who did For all types of hypomineralization, most children presented not participate in the main study, were examined in field condi- the condition in one tooth. Moreover, considering the severity tions. Subsequently, another 10 children were examined, and of the hypomineralization, at least 70 percent of the affected the inter- and intra-agreements of the examiners were obtained. teeth presented mild to moderate hypomineralization for pri- The examinations were conducted at the schools using a mary second molars, primary canines, and permanent first portable dental chair and artificial light and began by record- molars.