Distribution and severity of molar hypomineralisation: trial of a new severity index

Computerised assessment-a novel approach for calculation of percentage of hypomineralized lesion on incisors and its correlation with aesthetic concern

Introduction

Molar-incisor hypomineralization (MIH) is a localized, qualitative, demarcated enamel defect that affects first permanent molars (FPMs) and/or permanent incisors. The aim of present study was to introduce a novel computerised assessment process to detect and quantify the percentage opacity associated with MIH affected maxillary central incisors.

Methodology

Children (8-16 years) enrolled in the primary study having mild (white/cream or yellow/brown) MIH lesion on fully erupted maxillary permanent central incisor. 50 standardised images of MIH lesions were captured in an artificially lit room with fixed parameters and were anonymized and securely stored. Images were analysed by AI-driven computerised software and generates output classifications via a sophisticated algorithm crafted using a meticulously annotated image dataset as reference through supervised machine learning (SML). For the validation of computerised assessment of MIH lesions, the percentage of demarked opacity was calculated using ADOBE PHOTOSHOP CS7.

Results

The percentage of MIH lesion was calculated through histogram plotting with the maxima ranging from 7.29 % to 71.21 % with the mean value of 34.51 %. The validation score ranged from 10.29 % to 67.27 % with the mean value of 35.32 %. The difference between the two was statistically not significant. Out of 50 patients; 11 patients had 1-30 % of surface affected with MIH and 2 had aesthetic concern; 24 had 30-60 % of surface affected and 13 had aesthetic concern; 15 had >60 % of surface affected and 12 had aesthetic concerns.

Conclusions

The proposed approach exhibit sufficient quality to be integrated into a dental software addressing practical challenges encountered in daily clinical settings.

The Impact of Molar Incisor Hypomineralisation on Children and Adolescents: A Narrative Review

Molar incisor hypomineralisation (MIH) is a qualitative developmental enamel defect with a prevalence of 13% worldwide. This review aims to outline the current evidence regarding the impact of MIH on children's oral health and, more broadly, their day-to-day activities. MIH is associated with negative sequelae, including hypersensitivity, post-eruptive breakdown, the rapid development of carious lesions and poor aesthetics. Other concerns pertain to the clinical management of MIH and include difficulty in achieving local anaesthesia, increased dental fear and anxiety (DFA) and increased behaviour management problems. Oral health-related quality of life (OHRQoL) is the most standardised measure of patient impact; however, no instruments have been validated for use in MIH populations. The few existing observational studies investigating the impact of MIH on OHRQoL in children have produced conflicting results. Interventions to alleviate hypersensitivity and improve aesthetics had a positive impact on the OHRQoL of MIH-affected children. Multiple methodological issues make it difficult to measure the impact of MIH, including heterogeneity in the MIH severity classification, an overlap in the indices used to diagnose dental caries and MIH as well as the subjectivity of outcome measures for hypersensitivity and DFA.

Association of dental hypersensitivity and anxiety in children with molar-incisor hypomineralisation (MIH)

AIM

The objective of this study was to investigate whether dental hypersensitivity and dental fear were linked to the presence and severity of MIH.

METHODS

For this cross-sectional study, 1830 students between the ages of 6 and 12 years were recruited from four randomly selected schools. The Children's Fear Survey Schedule-Dental Subscale questionnaire was used to assess dental anxiety and fear. The children's self-reported dental hypersensitivity resulting from MIH was evaluated using the Wong-Baker Facial Scale and the Visual Analog Scale (VAS).

RESULTS

MIH was correlated with tooth hypersensitivity, particularly in severe cases. Dental fear was present in 17.4% of the children with MIH, but it was not associated with dental hypersensitivity, gender, or age.

CONCLUSION

No association was found between dental fear and dental hypersensitivity in children with MIH.

Making white spots disappear! Do minimally invasive treatments improve incisor opacities in children with molar-incisor hypomineralisation?

BACKGROUND

Children with molar-incisor hypomineralisation (MIH) frequently seek aesthetic treatment for incisor opacities. Surprisingly, few studies have evaluated the clinical success of such interventions.

AIM

To quantify the effectiveness of minimally invasive treatments in reducing enamel opacity visibility in children with MIH.

DESIGN

This in vitro study used digital clinical images of 23 children aged 8-16 years with MIH who underwent microabrasion and/or resin infiltration for the management of incisor opacities. Standard images were taken pre-treatment and 6 months post-treatment. Image software (Image-Pro Plus^® V7) was employed to convert 24-bit RGB images to 16-bit greyscale and 145× magnification. Measurement repeatability was assessed using intra-class correlation coefficients (ICCs). Post-treatment changes in visible opacity area (mm² ) and brightness (greyscale value) were tested using the Wilcoxon signed-rank test for related samples.

RESULTS

The mean total opacity surface area significantly reduced from 14.3 mm² (SD = 7.5) to 9.4 mm² (SD = 9.0) post-treatment. The proportion of tooth surface affected by the opacity also significantly reduced from 22.5% (SD = 10.5) to 14.7% (SD = 12.7). The mean maximum opacity brightness significantly reduced from 53 066 greyscale value (SD = 4740) to 49 040 (SD = 3796). ICC was good/excellent (0.75-1.0).

CONCLUSION

Minimally invasive treatment is effective in reducing the size and brightness of discrete incisor opacities. Future research should compare objective findings with patient-reported outcomes.

Are yellow-brownish opacities in hypomineralized teeth more prone to breakage than white-creamy ones? A systematic review

OBJETIVE

To evaluate all the available evidence assessing if in hypomineralized teeth, yellow-brownish opacities are more prone to post-eruptive breakdown (PEB) compared to white-creamy opacities.

MATERIALS AND METHODS

Observational studies that evaluated the occurrence of PEB in hypomineralized teeth were considered for inclusion. Electronic searches were performed up to January 2022 in MedLine, LILACS, BBO, Cochrane Library, Web of Science, Scopus, and EMBASE. Neither publication date nor language restrictions were imposed to the searches. Two researchers independently performed the study selection, data extraction, and quality assessment of the included studies according to the Newcastle-Ottawa Scale (NOS). Datasets from studies were grouped for narrative synthesis based on the severity of the PEB (enamel or dentin), type of tooth (molar or incisor), unit of analysis (subject or tooth or tooth surface), and follow-up period (in months). The certainty of evidence was evaluated using the GRADE approach.

RESULTS

Nine studies were included, five cohort and three cross-sectional. All studies assessed the opacities and PEB by visual examination and diagnosed MIH according to EAPD criteria. In the cohort studies, considering all follow-up periods (ranging from 6 to 36 months), dark opacities fractured more than light opacities, at both enamel and enamel/dentin levels, and molars fractured more than incisors. In two out of three cross-sectional studies, dark opacities also fractured more than light opacities, but the deep of the PEB (enamel or dentin breakdown) or the type of tooth (molar or incisor) was not considered in the analysis.

CONCLUSION

Although it seems plausible to state that darker demarcated opacities in MIH patients broke more often than light ones, based on this systematic review of the literature, the certainty of the available evidence about this association is still very low.

CLINICAL RELEVANCE

More reliable and valid research is still necessary to support any future recommendation that MIH children who present yellow-brownish opacities should be monitored at shorter intervals compared to those who present only white-creamy opacities.

Full coverage crowns for rehabilitation of MIH affected molars: 24 month randomized clinical trial

BACKGROUND

Teeth affected with severe molar incisor hypomineralization (MIH) require extensive restorations, which do not last for a long time and often require treatment in the form of onlays or full coverage restorations.

AIM

To evaluate and compare the clinical performance of zirconia, lithium disilicate, and cast metal crowns as full-coverage restorations on MIH-affected first permanent molars (FPMs).

METHODS

60 MIH affected FPMs requiring full-coverage crowns were identified in children aged 8-15 years and were randomly allocated to the three treatment groups according to the type of full coverage restoration received using block randomization technique. After an adequate removal of the MIH defect and restoration with composite resin, the tooth preparation was done followed by fabrication of crown and its cementation using resin cement. The intergroup comparison was done on the basis of USPHS criteria, gingival, plaque scores, patient and parents acceptance through a visual analog scale to decipher their clinical performance at 6, 12, 24 months.

RESULTS

After 24 months, the crowns showed similar clinical success in terms of the criterias used to compare their clinical performance. The retention, marginal adaptation, relief from hypersensitivity, proximal contact, gingival health with no statistically significant difference among the three groups.

CONCLUSION

Based on the observations, Lithium disilicate, Zirconia and full cast metal crowns showed similar clinical success in rehabilitation of First permanent molars with severe MIH over 24 months of evaluation. The clinical success is not influenced by the material of the restoration. However, prospective studies with a longer follow-up are required to reach a more definitive conclusion.

Evaluation of developmentally hypomineralised enamel after surface pretreatment with Papacarie Duo gel and different etching modes: an in vitro SEM and AFM study

PURPOSE

This study aimed at investigating the surface morphology and nanotopography of normal enamel (NE) and developmentally hypomineralised enamel (HE) when subjected to various pretreatment protocols under scanning electron microscopy (SEM) and atomic force microscopy (AFM).

METHODS

Sixteen NE, 16 creamy/white (CW) HE and 16 yellow/brown (YB) HE specimens sectioned from extracted hypomineralised first permanent molars (FPMs) were included in this study. They were randomly distributed into 12 experimental groups (n = 4). Each group involved the following: (1) deproteinisation with Papacarie Duo^® gel or no deproteinisation, and (2) the use of Scotchbond™ Universal Adhesive (Scotchbond) in self-etch (SE) mode or 37% phosphoric acid etchant. Subsequently, the surface morphology and nanotopography of pretreated enamel specimens were evaluated under SEM and AFM, respectively.

RESULTS

SEM observation showed that deproteinisation with Papacarie Duo^® gel before phosphoric acid etching led to favourable etching patterns. This was consistent across all groups irrespective of the type of enamel specimen and the severity of hypomineralisation. In contrast, AFM results identified three factors that influenced surface parameters: (1) type of enamel specimen, (2) severity of hypomineralisation and (3) etching mode. YB HE recorded higher surface roughness values than CW HE and NE when subjected to the same pretreatment protocol. Deproteinisation and the application of Scotchbond in SE mode led to minimal topographic changes; however, acid etching was associated with an increase in surface roughness.

CONCLUSION

Deproteinisation with Papacarie Duo^® gel followed by acid etching contributed to improved etching patterns on HE.

Molar Incisor Hypomineralisation: Current Knowledge and Practice

BACKGROUND

Molar incisor hypomineralisation (MIH) is a common developmental dental condition that presents in childhood. Areas of poorly formed enamel affect one or more first permanent molars and can cause opacities on the anterior teeth. MIH presents a variety of challenges for the dental team as well as functional and social impacts for affected children.

OBJECTIVES

Here, we provide an up-to-date review of the epidemiology, aetiology, diagnosis and clinical management of MIH.

MATERIALS AND METHODS

A review of the contemporary basic science and clinical literature, relating to MIH, was undertaken using information obtained (up to 10 April 2020) from the electronic databases PubMed, Scopus, Web of Science and the Cochrane Library.

RESULTS

There is a growing body of evidence relating to the aetiology, presentation and clinical management of MIH. Current knowledge appears to be focused on potential genetic aspects, as well as the development and validation of indices for the diagnosis and management of MIH. There has also been increasing recognition of the global and individual burden of this common condition.

CONCLUSIONS

Dental health professionals should regularly appraise the basic science and clinical MIH literature to ensure that they provide the best possible short- and long-term care for their young patients.

Molar incisor hypomineralization (MIH): prevalence and degree of severity in a Mexican pediatric population living in an endemic fluorosis area

OBJECTIVE

To estimate the prevalence and severity of molar incisor hypomineralization (MIH) in 8 years old children living in an endemic fluorosis area.

METHODS

MIH prevalence rate was determined from a study sample comprising 613 participants. They were recruited from 11 urban public schools with similar socio-economic status. Oral evaluations were performed and diagnosed MIH teeth were classified under Ghanim et al.'s criteria. Statistical descriptive and comparative analyzes were carried out.

RESULTS

First permanent molars were the tooth group most affected, followed by the upper central incisors, lower central incisors, lower lateral incisors, and upper lateral incisors. There was no significant statistical difference by gender and by maxillary/mandible arches (P = 0.82 and 0.26, respectively). The frequency of MIH was more in molars compared to incisors (P < 0.02).

CONCLUSIONS

The MIH prevalence in this study was 12.4 percent. According to the MIH severity, degree 2 was the most frequently detected (76.4 percent).

Orthodontic treatment of children with class II division 1 with severe MIH involving first permanent molars extractions: A case report

BACKGROUND

Class II division 1 is the most common malocclusion in Europe. When the overjet is severe, the risk of trauma on anterior maxillary teeth as well as the risk of being bullied at school is increased. From this point of view, early treatment reduces the risk of dental fracture and increases patient self-esteem. In another hand, MIH is frequent with a prevalence of around 15% in children with country specificity, and molars in particular are difficult to treat endodontically with good long-term results when the MIH is severe. In many cases when the third molars are present, the extraction of the affected teeth followed by an orthodontic treatment remains the best solution but requires adequate orthodontic mechanics.

OBJECTIVE

The purpose of this article is to display one case of class II division1 with MIH treated by orthopaedic therapy and followed by molar extractions and fixed appliance.

Evaluating the changes in molar incisor hypomineralization prevalence: A comparison of two cross-sectional studies in two elementary schools in Mexico City between 2008 and 2017

BACKGROUND

Little information is available on the trends over time of the prevalence of molar incisor hypomineralization (MIH). This condition may be preventing dental caries decline.

AIM

(a) To compare the prevalence of MIH, in Mexico City schoolchildren, evaluated in 2008 with a group evaluated in 2017, (b) to identify the association of MIH with dental caries, and (c) to assess the mother's perception of her child's oral health status.

DESIGN

Two cross-sectional studies performed in 2008 and in 2017 were compared. The oral examiner and the selected schools were the same in both surveys.

RESULTS

A total of 549 schoolchildren were evaluated. The prevalence of MIH in the first survey was 20.3%, and 31.9 % in the second survey, (p = .002). Children with MIH were more likely to have dental caries. The odds ratio was 2.24 (p = .036) and 4.18 (p ˂ .001) in the first and second surveys, respectively. Mothers of children with MIH perceived worse oral health status of their children than the mothers whose children did not have MIH (odds ratio = 4.47, p ˂ .001).

CONCLUSION

The findings portray a clear increase in prevalence of MIH and highlight the need for increased awareness about this condition among dentists and the general population.

Molar incisor hypomineralisation in Lebanon: prevalence and clinical characteristics

BACKGROUND

Molar incisor hypomineralisation (MIH) is a qualitative enamel developmental defect affecting 1-4 first permanent molars and sometimes the permanent incisors. MIH is extremely widespread around the world and presents a considerable clinical problem in paediatric dentistry. Although, little prevalence data exist for Middle East populations including the Lebanese one.

AIM

The objectives of this study were to investigate the prevalence of MIH in 7-9-year-old Lebanese children, with relevance to gender, jaw and side distribution, and to assess the clinical status, extent and severity of MIH lesions of the affected teeth.

DESIGN

Representative sample (n = 659) of 7-9-year-old Lebanese children attending private and public schools distributed throughout Lebanon was examined for MIH. Clinical status, extent and severity of MIH lesions on FPMs and permanent incisors were scored using the short-form grading method (MIH index) of Ghanim et al. (Eur Arch Paediatr Dent 16:235-246, 2015).

RESULTS

An overall MIH prevalence of 26.7% was reported with no significant predilection for girls over boys. 52.8% of the cases present with only molars and. 47.2% with both molars and incisors and did not present any significant difference between upper and lower jaws (P = 0.325). Left-side FPMs were more affected than the right ones (P = 0.0218). Central incisors were significantly more affected than the laterals in both jaws (P < 0.0001). Maxillary central incisors were significantly more affected than their mandibular counterparts (P < 0.0001). Most of the clinical status was demarcated opacities extended on less than the third of the tooth surface. The extent of lesions correlated significantly with the number of affected molars. Most of the affected teeth presented with mild defects and the degree of severity was not correlated with gender but significantly increased with age.

CONCLUSIONS

MIH is prevalent in Lebanon. Further studies are required to analyse the possible systemic and environmental etiologies among Lebanese children.

Second primary molar hypomineralisation and drugs used during pregnancy and infancy. A systematic review

OBJECTIVES

Hypomineralised second primary molars (HSPM) are due to idiopathic hypomineralisation that affects from 1- to 4-s primary molars, and its aetiology remains unclear. Our objective was to systematically review studies in which the investigators had studied the association between HSPM and drug use during pregnancy and the first year of life.

MATERIALS AND METHODS

A systematic search for publications until July 2018 was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. No restrictions were placed on year of publication. The PECO Question was as follows: P, children exposed to drugs during pregnancy and the first year of life; E, drugs to which mothers, during pregnancy and their offspring were exposed; C, control groups from studies with the same characteristics not exposed to drugs during pregnancy and the first year of life; and O, relationship between drug exposure during pregnancy and the first year of life and HSPM. Two reviewers extracted the data and assessed the risk of bias using the Newcastle-Ottawa Scale criteria.

RESULTS

We initially identified 986 articles, or which seven were selected for review: two case-control studies, one cross-sectional studies and four cohort studies. Four studies reported data on drug consumption during pregnancy and four investigated drug use during the first year of life and the occurrence of enamel defects in primary dentition.

CONCLUSIONS

There is no clear evidence that the use of drugs during pregnancy and during the first year of life is associated with HSPM. Further well-designed prospective studies are needed.

CLINICAL RELEVANCE

Determining the etiological factors related to the development of HSPM would help to establish preventive protocols in patients at potential risk. As HSPM is predictive of molar incisor hypomineralisation (MIH), the application of preventive protocols would avoid complications in both the primary and permanent dentition.

On the Variable Clinical Presentation of Molar-Incisor Hypomineralization

Molar-incisor hypomineralization (MIH) is a condition that is defined based on its peculiar clinical presentation. Original reports on the etiology of the condition and possible risk factors were inconclusive, and we refuted the original suggestion that MIH is an idiopathic condition and suggested that MIH has complex inheritance and is due to the interaction of more than one gene and the environment. Our group was the first to suggest MIH has a genetic component that involves genetic variation in genes expressed during dental enamel formation. Later we expanded this work to include genes related to the immune response. In this report, we provide a rationale to explain the variation seen in the clinical presentation of MIH, which can affect just one molar out of the four or just a portion of a particular molar.

Tooth mineral density of different types of hypomineralised molars: a micro-CT analysis

AIM

This study sought to evaluate the tooth mineral density (TMD) for the different lesion types in hypomineralised first permanent molars (FPMs) and compare them to unaffected enamel in clinically sound FPMs.

DESIGN

Eighteen FPMs with varying degrees of hypomineralised enamel were grouped into brown, yellow/creamy and white lesion types. Micro-CT was used to determine the TMD for each lesion type, and for unaffected enamel at different locations in the outer, middle, and inner-third of the enamel.

RESULTS

The average TMD for brown, yellow/creamy, white and unaffected enamel was 1.79, 2.21, 2.43 and 2.46 g/cm³, respectively. Brown and yellow/creamy lesions exhibited a statistically significant difference when compared to white lesions and unaffected enamel. However, no statistical difference was evident in TMD between white lesions and unaffected enamel. The TMD increased from the outer-third to inner-third for brown and yellow/creamy lesions (p < 0.05), while in white lesions and unaffected enamel, the TMD decreased from the outer-third to inner-third (p < 0.05).

CONCLUSION

TMD was lowest for brown lesions followed by yellow/creamy lesions while the TMD for white lesions was similar to unaffected enamel.

Caries Experience in Children with and without Molar-Incisor Hypomineralisation: A Case-Control Study

Aim: The aim of this study was to compare the caries experience of children with and without molar-incisor hypomineralisation (MIH). Methods: A case-control study was designed in which 130 children aged between 7 and 13 years with MIH (cases) were matched with 130 children without the condition (controls) according to age, sex, and school. Dental caries and MIH were assessed using the Caries Assessment Spectrum and Treatment (CAST) and European Academy of Paediatric Dentistry (EAPD) criteria, respectively, by three examiners. CAST was converted into DMFT/dmft; the Kruskal-Wallis test was performed to analyse whether dmft/DMFT was influenced by the severity of MIH. Associations between MIH and dental caries were analysed at child and tooth levels: between and within subjects, respectively. To correlate MIH severity and the occurrence of dental caries, the Cochran-Armitage test was used. Results: The mean age of the children was 9.63 ± 1.29 years. The mean dmft for cases was 1.23 ± 1.99 and for controls 1.71 ± 2.22 (p > 0.05). For the DMFT, the mean scores for cases and controls were 0.45 ± 0.90 and 0.07 ± 0.25, respectively (p < 0.001). The between-subject analysis showed no difference in relation to enamel carious lesions; however, the prevalence of dentine carious lesions was significantly higher in children with MIH than in those without the condition. The same pattern was seen for the within-subject analysis. It was observed that the increase in MIH severity resulted in more teeth being affected by dentine carious lesions (p = 0.0003). Conclusion: Children with MIH presented a higher experience of caries in the permanent dentition than those without the condition. MIH was considered a risk factor for caries development.

Optical coherence tomography use in the diagnosis of enamel defects

Molar incisor hypomineralization (MIH) affects the permanent incisors and molars, whose undermineralized matrix is evidenced by lesions ranging from white to yellow/brown opacities to crumbling enamel lesions incapable of withstanding normal occlusal forces and function. Diagnosing the condition involves clinical and radiographic examination of these teeth, with known limitations in determining the depth extent of the enamel defects in particular. Optical coherence tomography (OCT) is an emerging hard and soft tissue imaging technique, which was investigated as a new potential diagnostic method in dentistry. A comparison between the diagnostic potential of the conventional methods and OCT was conducted. Compared to conventional imaging methods, OCT gave more information on the structure of the enamel defects as well as the depth extent of the defects into the enamel structure. Different types of enamel defects were compared, each type presenting a unique identifiable pattern when imaged using OCT. Additionally, advanced methods of OCT image analysis including backscattered light intensity profile analysis and enface reconstruction were performed. Both methods confirmed the potential of OCT in enamel defects diagnosis. In conclusion, OCT imaging enabled the identification of the type of enamel defect and the determination of the extent of the enamel defects in MIH with the advantage of being a radiation free diagnostic technique.

A practical method for use in epidemiological studies on enamel hypomineralisation

With the development of the European Academy of Paediatric Dentistry (EAPD) judgment criteria, there has been increasing interest worldwide in investigation of the prevalence of demarcated opacities in tooth enamel substance, known as molar–incisor hypomineralisation (MIH). However, the lack of a standardised system for the purpose of recording MIH data in epidemiological surveys has contributed greatly to the wide variations in the reported prevalence between studies. The present publication describes the rationale, development, and content of a scoring method for MIH diagnosis in epidemiological studies as well as clinic- and hospital-based studies. The proposed grading method allows separate classification of demarcated hypomineralisation lesions and other enamel defects identical to MIH. It yields an informative description of the severity of MIH-affected teeth in terms of the stage of visible enamel destruction and the area of tooth surface affected (i.e. lesion clinical status and extent, respectively). In order to preserve the maximum amount of information from a clinical examination consistent with the need to permit direct comparisons between prevalence studies, two forms of the charting are proposed, a short form for simple screening surveys and a long form desirable for prospective, longitudinal observational research where aetiological factors in demarcated lesions are to be investigated in tandem with lesions distribution. Validation of the grading method is required, and its reliability and usefulness need to be tested in different age groups and different populations.

Severity of MIH findings at tooth surface level among German school children

AIM

This study was to investigate the distribution and clinical characteristics of teeth diagnosed with MIH at surface and defect type level in a cohort of German children.

METHODS

The study cohort included 242 children diagnosed with MIH which had been recorded during the compulsory dental school examinations of 20 German primary schools. The subjects had been enrolled by cluster sampling. All children attended the second to fourth grade (age 7-10 years, mean 8.1 ± 0.8). The children were examined by five calibrated examiners (kappa = 0.9) after tooth brushing. The recording comprised teeth, surfaces, type and severity of MIH defects and was conducted using a portable light, mirrors and cotton rolls. MIH was registered according to the EAPD criteria. Defects <1 mm were not recorded. Statistical analysis included descriptive statistics and Spearman's correlation.

RESULTS

Most affected teeth were first permanent molars (71.4 %) followed by the maxillary central incisors (15.6 %). The most common defects were demarcated opacities (82.2 %), while the remaining 17.8 % of the affected teeth exhibited severe enamel defects. The most frequently affected surface in molars was the occlusal surface (72.4 %); in incisors, it was the buccal surface (73.5 %). There were no atypical restorations in the affected incisors. Different types of MIH defects at various surfaces of the same tooth were common. The number of affected tooth surfaces was positively correlated with the severity of MIH at child (p < 0.001).

CONCLUSIONS

The study demonstrates severe enamel defects involving in almost one-fifth of all MIH teeth. The knowledge of the intra-oral distribution and severity of MIH findings at the enamel surface level is important for assessing the treatment needs.

The effect of resin infiltration and oxidative pre-treatment on microshear bond strength of resin composite to hypomineralised enamel

BACKGROUND

Reduced bond strengths of resin composites to hypomineralised enamel increase restorative failure.

AIM

To investigate if the adhesion of resin composite to hypomineralised enamel can be improved by pre-treatments: resin infiltration, oxidative pre-treatment followed by a resin infiltration, or oxidative pre-treatment.

DESIGN

Twenty-one enamel specimens in each of five Groups: 1) Normal enamel; 2) Hypomineralised enamel; 3) Hypomineralised enamel pre-treated with a resin infiltrant, (Icon(®)); 4) Hypomineralised enamel pre-treated with 5.25% sodium hypochlorite then treatment with resin infiltrant; 5) Hypomineralised enamel pre-treated with 5.25% sodium hypochlorite. A resin composite rod was bonded to each specimen using Clearfil™ SE bond as the adhesive (hereafter termed 'routine bonding'), then subjected to microshear bond strength (MSBS) testing.

RESULTS

Overall, the mean MSBS between the five groups differed significantly (P = 0.001). Pre-treatment of hypomineralised enamel with 5.25% sodium hypochlorite with or without subsequent resin infiltration in Groups 4 and 5 prior to routine bonding resulted in increased mean MSBS compared to Groups 2 and 3, with mean MSBS values not differing significantly when compared to routine bonding to normal enamel.

CONCLUSION

Increased bond strength of resin composite to hypomineralised enamel was obtained by pre-treatment of hypomineralised enamel specimens with 5.25% sodium hypochlorite with or without subsequent resin infiltration.