Treatment management of first permanent molars in children with Molar-Incisor Hypomineralisation

Treatment management of first permanent molars in children with Molar-Incisor Hypomineralisation N. KOTSANOS*, E.G. KAKLAMANOS**, K. ARAPOSTATHIS* ABSTRACT. Aim To study the treatment management of first permanent molars in children with Molar-Incisor Hypomineralisation (MIH). Study design Retrospective analysis. Methods The records of the clientele of a private paediatric dental practice were scanned. Thirty-six cases of children fulfilling the diagnostic criteria of MIH were retrieved who had been followed for a mean period of 4.5 years, and 36 children of matching age and gender, and with similar follow-up period, were randomly selected from the same clientele to serve as controls. Results Children in the MIH group exhibited greater DMFS and smaller dmfs scores. The frequency of restorative intervention was greater in children of the MIH group (OREST=11.00, 95% C.I. 2.85-42.45). Stainless-steel crowns had been placed only on MIH group molars. The follow-up records revealed that only restorations in the MIH group needed retreatment. Fillings and sealants in the MIH group had a greater probability of needing retreatment than in the control group (OREST=3.10, 95% C.I. 1.60-6.01). Conclusions Children affected by MIH may need to undergo a significant amount of restorative treatment at an early age. Moreover, fillings and sealants in MIH affected children have a greater probability of needing retreatment than in control group children. KEYWORDS: Molar-Incisor Hypomineralisation, Treatment, Retreatment needs. Introduction Weerheijm et al. [2001a] suggested the term Molar- Incisor Hypomineralisation (MIH) to describe the clinical finding of hypomineralisation of a systemic origin of one or more of the four permanent molars, as well as any associated and affected incisors. Clinically, the hypomineralisation defects involve altered translucency in demarcated areas of enamel. The defective opaque enamel is of normal thickness with a smooth surface and can be white-yellow or yellowbrown in colour. Occasionally, depending on the degree of sub-surface porosity, posteruptive enamel breakdown may occur under masticatory forces [Koch et al., 1987; Alaluusua et al., 1996a; 1996b; 1999; Jälevik and Norén, 2000; Leppäniemi et al., 2001; Weerheijm et al., 2001b; Hölltä et al., 2001]. In the literature, several factors capable of disturbing normal enamel development have been associated with these defects [Alaluusua et al., 1996a; 1996b; 1999; Hölltä et al., 2001; Jälevik, 2001; Jälevik et a.l, 2001a; Van Amerongen and Kreulen, 1995; Jälevik and Norén, Depts of *Paediatric Dentistry, **Preventive Dentistry, Periodontology and Implant Biology, Aristotle University of Thessaloniki, Greece. kotsanos@dent.auth.gr 2000; Beentjes et al., 2002]. The developmental defects observed in MIH can create considerable discomfort to the child, concern to the parents and problems to the clinician regarding the management of the affected teeth [Fayle, 2003]. The last few years have seen a series of reports on treating such cases. Current information suggests that children presenting with this type of defect require extensive and often repeated restorative treatment [Leppäniemi et al., 2001; Jälevik and Klingberg, 2002]. There has also been research focused on evaluating different types of interventions and restorative materials [Lygidakis et al., 2003; Zagdwon et al., 2003]. However, more data is needed to establish improved clinical strategies, especially for treating severe cases of MIH. The present report is a retrospective study of the treatment needs and management of first permanent molars in children with MIH attending a paediatric dental practice. Materials and methods Participants. At the beginning of 2004 a retrospective study was initiated. The records of the clientele of a private paediatric dental practice were EUROPEAN JOURNAL OF PAEDIATRIC DENTISTRY 4/2005 179

N. KOTSANOS, E.G. KAKLAMANOS, K. ARAPOSTATHIS scanned from 1995, when MIH was diagnosed as a separate hypomineralisation entity. Subsequently, records of further treatment up to June 2005 were added to the study. The location of demarcated opacities and enamel breakdown had been recorded on a specially designed patient research data sheet. From a total of 50 cases fulfilling the diagnostic criteria of MIH [Weerheijm et al., 2003], 36 cases with a followup time exceeding 12 months were retrieved. Their characteristics are presented in the results section. Based on these characteristics a control group of 36 children of matching age and gender were randomly selected by means of two tables of random numbers, one for the males and one for the females. In both groups, the status of restorations of the first permanent molars (hereafter called molars) had been assessed at follow-up [Ryge, 1980], and new restorative needs met. Clinical examination, restorative treatment and follow up had been performed by the same paediatric dentist (NK). During their last followup 10% of the patients had been seen twice with at least one week between sessions, allowing intraexaminer reproducibility to be measured and Kappa score calculated (kappa score, 0.95). Details of medical history such as respiratory, ear or other infections, hospitalisation, fever >39 C etc., of both MIH and control patients had been recorded after personal interview with patients mother. Where mothers had been unsure, the patients health data booklet with all medical information recorded by their paediatrician had been inspected. Statistical analysis. The software SPSS version 11.5 was used for the analyses. In every non-parametric test (Mann & Whitney and Chi-square tests) the observed significance level was computed either with Fisher s exact test or with Monte Carlo simulation method [Mehta and Patel, 1996]. Differences were considered significant when a p-value of 0.05 or less was observed. Results Description of sample characteristics. The characteristics of the participants at the time of initial examination are presented in Table 1. Children in the MIH group exhibited statistically significantly greater DMFS and dmfs scores. From the 144 molars in the MIH group, 119 (82.6%) showed signs of hypomineralisation. No statistically significant difference was observed in the number of maxillary or mandibular molars affected, nor were there any significant associations between the number of affected molars and the presence of affected maxillary incisors, mandibular incisors or both. No statistically significant differences were observed regarding the medical history of the children of both groups during the first three years of life. Group MIH Control Significance Age (χ 2 age ± SD) 7.7 ± 1.3 7.5 ± 1.2 NS Gender* males 19 19 females 17 17 NS DS (χ 2 mean ± SD) 2.4 ± 3.0 0.8 ± 1.3 p=0.002 MS - - FS 0.3 ± 1.0 0.1 ± 0.2 NS DMFS 2.8 ± 3.2 0.8 ± 1.3 p=0.001 ds (χ 2 mean ± SD) 3.0 ± 4.5 5.6 ± 7.0 NS ms - 0.1 ± 0.8 fs 0.7 ± 1.6 3.7 ± 7.0 NS dmfs 3.8 ± 4.9 9.4 ± 8.4 p=0.002 % of caries free children 14% 11% NS The significance of the differences was analysed with Mann-Whitney test or by the χ 2 test. NS: Not significant, NA: Not applicable TABLE 1 - Characteristics of the participants at the time of initial examination in a study of MIH in Greek children. 180 EUROPEAN JOURNAL OF PAEDIATRIC DENTISTRY 4/2005

TREATMENT MANAGEMENT IN MIH The mean follow-up time (± SD) for the MIH children was 4.5 ± 2.9 years and 4.6 ± 2.2 years for the control group children (Mann-Whitney test, p=0.431). Management of first permanent molars. First treatments. On a child basis and the review of the records showed that 33 children (91.7%) in the MIH group and 18 children in the control group (50.0%) had at least one molar restored (χ 2 test, p=0.000). The odds ratio for having restorative intervention in at least one molar for MIH group children (33/3) compared to the control group children (18/18) was OREST=11.00 (95% C.I. 2.85-42.45). On an intervention basis. The overall management of molars at the time of first treatment can be seen in Table 2. In total, 136 interventions were placed in 133 molars in the MIH group and 130 in 124 molars in the control group. Altogether, significant differences between the children of the two groups were observed regarding the various types of intervention (χ 2 test, p=0.000). In the MIH group, of the 35 teeth sealed, 18 had signs of hypomineralisation and of the 101 teeth that received restorations, 96 had signs of hypomineralisation. Therefore, the odds ratio for having restorative intervention vs. sealing in MIH affected molars (96/18) compared to the control group molars (40/90) is OREST=12.00 (95% C.I. 6.42-22.45). A qualitative finding was that more multisurface restorations were placed in MIH molars, while restorations placed in the control group were usually small in the form of preventive resin restorations (PRRs). Stainless steel crowns had only been placed in the MIH group. No molars had been extracted in the two groups. Follow-up treatments. On a child basis, the review of the follow-up records revealed that 17 out of 36 children in the MIH group and 7 out of 36 children in the control group needed second treatment in the form of restoration on at least one molar (χ 2 test, p=0.023). The odds ratio for having a restoration as retreatments on at least one molar in the children of the MIH group (17/19) compared with the children of the control group (7/29) is OREST=3.70 (95% C.I. 1.29-10.63). Overall, the mean number of restoration treatments (± SD) for each MIH child was 3.7 ± 1.9 compared to 1.5 ± 1.6 for each control group (Mann-Whitney test, p=0.000). On an intervention basis, the needs for re-treatment can be seen in Table 3. Significant differences between the children of the two groups were observed regarding the need for re-treatment of each particular type of initial intervention (χ 2 test, p=0.000). In the control group, no restoration needed re-treatment, while out of the 16 sealants retreated, 11 showed signs of caries and were substituted with small composite resin fillings in the form of preventive resin restorations (PRR). In the MIH group, re-treatment was needed in 11/18, i.e. more than half of amalgams (mean replacement time being less than 3 years) and in 15/59 i.e. a quarter of the restorations of composite restorations (mean replacement time being 4 years). No molar treated with a stainless-steel crown (SSC) needed second intervention. The molars restored more than once were always hypomineralised. Of the 8 sealants retreated, Intervention MIH group Control group Sealants 35 90 (25.7%, 52.2 ± 34.0) (69.2%, 53.5 ± 25.1) Amalgam fillings 18 6 (13.2%, 41.2 ± 32.7) (4.6%, 36.0 ± 20.2) Composite resin fillings 59 34 (43.4%, 44.7 ± 31.6) (26.2%, 57.1 ± 27.3) Stainless-steels crowns 24 - (17.6%, 50.2 ± 23.3) Restorative intervention 101 40 (74.3%) (30.8%) Total interventions 136 130 TABLE 2 - Management of first permanent molars at the time of the first treatment (n% of total interventions) and follow-up time for every type of intervention (mean months ± SD). EUROPEAN JOURNAL OF PAEDIATRIC DENTISTRY 4/2005 181

N. KOTSANOS, E.G. KAKLAMANOS, K. ARAPOSTATHIS Intervention MIH group Control group Sealants 8 out of 35 16 out of 90 (22.9%, 33.0 ± 25.7) (17.7%, 55.6 ± 22.7) Amalgam fillings 11 out of 18 0 out of 6 (61.1%, 32.3 ± 30.3) (-) Composite resin fillings 15 out of 59 0 out of 34 (25.4%, 48.3 ± 30.6) (-) Stainless-steels crowns 0 out of 24 (-) (-) (-) Total 34 out of 136 16 out of 130 (25.0%, 39.53 ± 29.6) (12.3%, 55.6 ± 22.7) TABLE 3 - Summary of cases of affected molars needing re-treatment (n% of interventions) and time after first intervention (mean months ± SD). five had been placed on molars with hypomineralised areas. Six, including the previously mentioned five, had been replaced with a composite resin restoration. Sealants in the MIH group were retreated after a shorter period of time than sealants in the control group (Mann-Whitney test, p=0.039). In the MIH group, 34 out of 112 interventions, excluding SSC, as none had been placed in the control group, were retreated, compared with 16 out of 130 in the control group (χ 2 test, p=0.001). The odds ratio for re-treatments, i.e. replacing sealants and filling in the MIH group (34/78) compared to control group (16/114) is OREST=3.10 (95% C.I. 1.60-6.01). Considering only affected molars in the MIH group, 31 out of 90 interventions (sealants and fillings) had been retreated compared with 16 out of 130 in the control group (χ 2 test, p=0.000). The odds ratio for retreating sealants and fillings in MIH affected molars (31/59), compared to control group molars (16/114) is OREST=3.74 (95% C.I. 1.89-7.39). Discussion According to the findings of the present study, children exhibiting MIH have 11 times greater probability of undergoing restorative treatment in their first permanent molars compared with children of a control group. Moreover, fillings and sealants in MIH affected children have over 3 times a greater probability of needing re-treatment than interventions on children of the control group. Comparison with a control group not representative of the general population is justified because these children resided in the same geographical area as the MIH children, had been treated and re-evaluated by the same paediatric dentist, received similar hygiene instruction and could be followed for approximately the same length of time. The dmfs scores were much smaller in the study group than in the control group, as the latter was representative of the patient population of a private paediatric dental practice where nearly half of the practice children were referred by general dental practitioners. However, after the eruption of the first permanent molars, the situation was dramatically reversed and statistically significant greater DMFS scores were observed in MIH children. The difference in the caries experience can provide a rough evaluation of the substantially increased treatment needs in the permanent teeth of the study population. Moreover, children in the MIH group had an 11 times greater probability of receiving actual restorative treatment on at least one molar, than children in the control group. The finding that SSCs were only needed in the study population is indicative of the extensive defects to be restored in this group. On the other hand, restorations in the control group involved mainly PRRs. Thus, MIH has a significant impact on treatment needs, as previously reported [Leppäniemi et al., 2001; Jälevik and Klingberg, 2002]. The fragility of the defective areas may account for the increased number of restorations placed on MIH molars. This problem may be aggravated, as these molars are often sensitive and children avoid brushing them. This leads to increased plaque stagnation and caries development [Weerheijm, 2003]. 182 EUROPEAN JOURNAL OF PAEDIATRIC DENTISTRY 4/2005

TREATMENT MANAGEMENT IN MIH The mean number of restoration treatments in the MIH group was 2.5 times greater than in the control group. Jälevik and Klingberg [2002] reported similar, though more pronounced, differences. They observed that affected children had undergone dental treatment of their first permanent molars nearly 9 times more often than the children in a control group, and that every defective tooth had been on average treated twice. The extensive defects encountered in MIH affected teeth lead to extensive fillings, inevitably increasing the risk of failure. In addition, if clinically sound but opaque enamel is left during restoration, then it may disintegrate later, or problems of adhesion to the hypomineralised tissue may be encountered [Weerheijm, 2003]. In our study population, no molar restored with a stainless steel crown needed retreatment, in agreement with Zagdwon et al., [2003]. Lygidakis et al., [2003] showed that the use of composite restorations in molars with at least two sound surfaces produced satisfactory long-term results. Apart from the restorations placed in MIH affected molars, sealants were found to need retreatment almost two years earlier than sealants in the control group. Retreatment of amalgam restorations was more than twice as frequent compared with composite resin restorations, which is in agreement with Fayle s [2003] suggestion of preferring composites for MIH affected molars, and it is further supported by Lygidakis et al. [2003] results. However, Mejàre et al. [2005] reported similar success rates for composite and amalgam restorations. The fact that in their study population, teeth with more extensive and possibly carious defects where amalgam fillings are conventionally placed, were extracted, may account for the contradictory results. In addition, their finding of restoration longevity similar to the general population may be attributable to the same treatment strategy. There seems to be a feeling that, with the increasing awareness of the carious and attritional deterioration of these molars, better and longer lasting restorations are being placed nowadays. Current and future treatment of such molars is being documented in new cases and it will be interesting to compare their re-treatment with results reported here and elsewhere [Jälevik and Klingberg, 2002; Mejàre et al., 2005]. In our study sample, no molars had been extracted, although extractions of affected molars have also been proposed as a treatment alternative. Mejàre et al. [2005] compared cases of restored MIH affected teeth to cases where severely defective teeth had been extracted, sometimes followed by orthodontic correction. They observed that at the age of 18 years, individuals were equally satisfied with their dental situation, irrespective of the type of treatment they had undergone, and suggested the option of extracting severely defective molars. However, the authors of the present study believe that this subject warrants further investigation. Our data did not support other reports [Koch et al., 1987; Jälevik et al., 2001b; Weerheijm et al. 2001a] suggesting a relationship between the number of affected molars and the presence of defective areas in maxillary incisors, mandibular incisors, or both. Mejàre et al. [2005] also reported a lack of any statistically significant relationship between the number of molars with enamel surface breakdown and the number of incisors with enamel hypomineralisation. Moreover, no statistically significant frequency of occurrence was observed in the number of affected maxillary or mandibular molars, which is in agreement with Weerheijm et al. [2001b]. Leppäniemi et al. [2001] reported more maxillary molars affected. Contrary to other reports [Van Amerongen and Kreulen, 1995; Jalevik and Noren, 2000; Jalevik, 2001; Jalevik et al., 2001a; Beentjes et al., 2002] no statistically significant differences were observed in medical history during the first three years of life between the two groups. Conclusion Based on the available data, the current study suggests that MIH has a significant impact on treatment needs. Moreover, close follow up of all interventions placed on affected teeth may be indicated, as they seem to exhibit decreased survival. These findings point to the need for better clinical strategies in treating MIH molars. References Alaluusua S, Lukinmaa P-L, Vartiainen T et al. Polychlorinated dibenzo-p-dioxins and dibenzofurans via mother's milk may cause developmental defects in the child's teeth. Environ Toxicol Pharmacol 1996a;1:193-197. Alaluusua S, Lukinmaa PL, Koskimies M et al. Developmental dental defects associated with long breast feeding. Eur J Oral Sci 1996b;104(5-6):8493-497. Alaluusua S, Lukinmaa PL, Torppa J, Tuomisto J, Vartiainen T. Developing teeth as biomarker of dioxin exposure. Lancet 1999; 353: 206. Beentjes VE, Weerheijm KL, Groen HJ. Factors involved in the aetiology of molar-incisor hypomineralisation (MIH). Eur J Paediatr Dent 2002; 3(l): 9-13. EUROPEAN JOURNAL OF PAEDIATRIC DENTISTRY 4/2005 183

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