An investigation into the effect of a resin infiltrant on the micromechanical properties of hypomineralised enamel

Influence of different pre-treatments on the resin infiltration depth into enamel of teeth affected by molar-incisor hypomineralization (MIH)

OBJECTIVES

This in vitro pilot study aimed to evaluate whether different pre-treatments (demineralization, deproteinization, (chemo-)mechanical reduction of the surface layer) influence the penetration depth of a resin infiltrant into MIH-affected enamel compared to initial carious lesions.

METHODS

Thirty extracted human permanent molars with non-cavitated initial carious lesions (n = 5) or MIH (n = 25) were chosen and randomly assigned to six experimental groups: IC: initial caries; M: MIH; MN: MIH, 5.25% sodium hypochlorite; MM: MIH, microabrasion; MA: MIH, air abrasion; MAN: MIH, air abrasion and 5.25% sodium hypochlorite. A modified indirect dual fluorescence staining method was adopted to assess the penetration depth (PD) of the resin infiltrant and the lesion depth (LD) by confocal laser scanning microscopy (CLSM). Exemplarily, scanning electron microscopic (SEM) images were captured. The relationship between group assignment and penetration/lesion depth was estimated using a linear mixed model incorporating the tooth as random effect (two observations/tooth). The significance level was set at p < 0.05.

RESULTS

For MIH-affected molars, the mean PD (in µm; median, [minimum-maximum]) were M (178.2 [32.5-748.9]), MN (275.6 [105.3-1131.0]), MM (48.7 [0.0-334.4]), MA (287.7 [239.4-491.7]), and MAN (245.4 [76.1-313.5]). Despite the observed differences in PD between the groups, these could not be statistically verified (Bonferroni, p = 0.322). The percentage penetration was significantly higher for IC than for MIH groups (Bonferroni, p < 0.05).

SIGNIFICANCE

Compared to IC, resin infiltration into MIH-affected enamel ist more variable. Different pre-treatments influence the resin penetration into developmentally hypomineralized enamel to a fluctuating level.

Management of permanent incisors affected by Molar-Incisor-Hypomineralisation (MIH) using resin infiltration: a pilot study

PURPOSE

To compare the aesthetic improvement of Molar-Incisor-Hypomineralisation (MIH) opacities treated by applying Icon-Etch for three cycles with the opacities treated by Icon-Etch for once, in the course of resin infiltration technique.

METHODS

Thirty incisors were sorted based on the colour of the opacities and then distributed according to the number of Icon-Etch cycles using a randomisation table into the groups: (1) White/Creamy one cycle, (2) White/Creamy three cycles, (3) Yellow/Brown one cycle, (4) Yellow/Brown three cycles. The primary outcomes of applying the resin infiltration to the opacities were compared amongst groups according to the parents' satisfaction, the amount of coverage, and the colour matching with the surrounding sound enamel. The stability of the results after 3 months was evaluated using a spectrophotometer.

RESULTS

The colour of the opacity pre-treatment affected the outcomes significantly (p < 0.05), compared according to the method of application (p > 0.05) in terms of parents' satisfaction. Whilst the multiple applications for Icon-Etch cycles showed more coverage amount in White/Creamy opacities than the application ones (p < 0.05); in colour matching, there was no statistically significant difference between the two methods (p > 0.05). For yellow/brown opacities, some negative results occurred with the single Icon-Etch cycle.

CONCLUSION

In MIH opacities, it is possible to rely on the resin infiltration as a minimally invasive method to achieve acceptable results, especially with multiple Icon-Etch cycles applications in the white/creamy opacities. The colour stability has not been affected by either the colour of the opacity or the number of cycles.

Short-term Results of the Masking Effect of an Infiltrant Resin on Mild Molar Incisor Hypomineralization Lesions in Anterior Teeth

This non-controlled clinical study evaluated the masking effect of an infiltrant resin on mild molar incisor hypomineralization (MIH) lesions. Thirty MIH-affected anterior teeth with creamy/ white opacities from 12 children aged 6-15 years received the application of an infiltrant resin (Icon- DMG). Standard photographs were taken before (T1), immediately after (T2), and 1 week after (T3) resin infiltration. Two calibrated examiners qualitatively analyzed the color match using the Fédération Dentaire Internationale (FDI) scale. The binomial distribution test analyzed the scores of the color match at T1 with T2 and T3, and McNemar's test analyzed the scores of the color match between T2 and T3 (α=0.05). There was a significant increase in color match between T1 and T2 (p=0.0005), between T1 and T3 (p=0.0005), and between T2 and T3 (p=0.0019). It was concluded that infiltrant resin was effective in improving the esthetic appearance of creamy/white opacities on MIH-affected anterior teeth.

Best clinical practice guidance for clinicians dealing with children presenting with molar-incisor-hypomineralisation (MIH): an updated European Academy of Paediatric Dentistry policy document

AIM

To update the existing European Academy of Paediatric Dentistry (EAPD) 2010 policy document on the 'Best Clinical Practice guidance for clinicians dealing with children presenting with Molar-Incisor-Hypomineralisation (MIH).'

METHODS

Experts, assigned the EAPD, worked on two different topics: (A) Aetiological factors involved in MIH, and (B) Treatment options for the clinical management of MIH. The group prepared two detailed systematic reviews of the existing literature relevant to the topics and following a consensus process produced the updated EAPD policy document on the 'Best Clinical Practice guidance for clinicians dealing with children presenting with molar-incisor-hypomineralisation (MIH).' The GRADE system was used to assess the quality of evidence regarding aetiology and treatment which was judged as HIGH, MODERATE, LOW or VERY LOW, while the GRADE criteria were used to indicate the strength of recommendation regarding treatment options as STRONG or WEAK/CONDITIONAL.

RESULTS

(A) Regarding aetiology, it is confirmed that MIH has a multifactorial aetiology with the duration, strength and timing of occurrence of the aetiological factors being responsible for the variable clinical characteristics of the defect. Perinatal hypoxia, prematurity and other hypoxia related perinatal problems, including caesarean section, appear to increase the risk of having MIH, while certain infant and childhood illnesses are also linked with MIH. In addition, genetic predisposition and the role of epigenetic influences are becoming clearer following twin studies and genome and single-nucleotide polymorphisms analyses in patients and families. Missing genetic information might be the final key to truly understand MIH aetiology. (B) Regarding treatment options, composite restorations, preformed metal crowns and laboratory indirect restorations provide high success rates for the posterior teeth in appropriate cases, while scheduled extractions provide an established alternative option in severe cases. There is great need for further clinical and laboratory studies evaluating new materials and non-invasive/micro-invasive techniques for anterior teeth, especially when aesthetic and oral health related quality of life (OHRQoL) issues are concerned.

CONCLUSIONS

MIH has been studied more extensively in the last decade. Its aetiology follows the multifactorial model, involving systemic medical and genetic factors. Further focused laboratory research and prospective clinical studies are needed to elucidate any additional factors and refine the model. Successful preventive and treatment options have been studied and established. The appropriate choice depends on the severity of the defects and the age of the patient. EAPD encourages the use of all available treatment options, whilst in severe cases, scheduled extractions should be considered.

An update of treatment modalities in children and adolescents with teeth affected by molar incisor hypomineralisation (MIH): a systematic review

PURPOSE

To systematically review the treatment modalities for molar-incisor hypomineralisation for children under the age of 18 years. The research question was, 'What are the treatment options for teeth in children affected by molar incisor hypomineralisation?'

METHODS

An electronic search of the following electronic databases was completed MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, LILACS, Google Scholar and Open Grey identifying studies from 1980 to 2020. The PRISMA guidelines were followed. The studies were screened, data extracted and calibration was completed by two independent reviewers.

RESULTS

Of 6220 potential articles, 34 studies were included. Twenty studies investigated management of molars with fissure sealants, glass ionomer cement, polyacid modified resin composite, composite resin, amalgam, preformed metal crowns, laboratory-manufactured crowns and extractions. In four articles management of incisors with microabrasion, resin-infiltration and a combination of approaches was reported. Eight studies looked at strategies to mineralise MIH-affected teeth and/or reduce hypersensitivity. Two studies investigated patient-centred outcomes following treatment. Due to the heterogeneity between the studies, meta-analysis was not performed.

CONCLUSION

The use of resin-based fissure sealants, preformed metal crowns, direct composite resin restorations and laboratory-made restorations can be recommended for MIH-affected molars. There is insufficient evidence to support specific approaches for the management of affected incisors. Products containing CPP-ACP may be beneficial for MIH-affected teeth.

The influence of lesion characteristics on application time of an infiltrate applied to MIH lesions on anterior teeth: An exploratory in vivo pilot study

OBJECTIVES

To evaluate the factors that influences the kinetics of resin infiltration of molar incisor hypomineralisation (MIH) lesions on permanent anterior teeth.

METHODS

Demarcated MIH lesions with homogeneous and heterogeneous lesion body appearance, Types 1 (n = 14) and 2 (n = 18), respectively, were selected. After removal of the lesion surface layer using a tapered diamond finishing bur, the lesions were etched and ethanol was applied to the lesions and it was determined if the lesion was still visible or not. Images were taken just prior infiltrant (Icon; DMG) application (T₀), during the infiltration process (T_x) and when infiltration had ceased progressing or opacity disappearance was clinically apparent (T_max). Surface-area measurements of the opacity and infiltrated area were calculated and the infiltration proportion (IP_x) was calculated over the infiltration time.

RESULTS

Type 1 and positive ethanol test lesions showed significantly lower mean T_max (3.4 min) in comparison with Type 2 and negative ethanol test lesions (9.9 min) [Student t-test/Fisher's exact test; p < .01]. A non-linear correlation was observed (R² = 0.88) indicating that the IP_x was rapid at the beginning of resin application, decreasing over time.

CONCLUSION

In comparison with Type 1 and positive ethanol test lesions, Type 2 and negative ethanol test lesions require longer application time to infiltrate.

CLINICAL SIGNIFICANCE

MIH-lesion type and the 'ethanol test' were reliable predictive factors for the application time required for infiltrating MIH lesions on permanent anterior teeth.

Molar incisor hypomineralization: A review and prevalence in Japan

Molar incisor hypomineralization (MIH) is defined as hypomineralization of systemic origin of one to four first permanent molars, and incisors are also frequently affected. This disorder is a serious concern in pediatric dentistry. Teeth affected by MIH have many dental problems, such as hypersensitivity, poor aesthetics, and rapid progression of dental caries. The prevalence of MIH ranges from 2.8% to 21% among studies with more than 1000 subjects in different countries and age groups. The etiology of MIH is unclear, but genetic and environmental factors have been proposed. This review describes the prevalence, etiology, and clinical management of MIH. A detailed description of MIH prevalence in Japan is also provided.

Structural integrity of MIH-affected teeth after treatment with fluoride varnish or resin infiltration: An 18-Month randomized clinical trial

OBJECTIVE

To evaluate the influence of fluoride varnish (FV) therapies or resin infiltration (RI) to maintain the structural integrity of Molar Incisor Hypomineralization (MIH) -affected teeth.

METHODS

Fifty-one children aged 6-12 years with at least one incisor and one first permanent molar with yellow/brown MIH opacities were included. Patients were randomly allocated into three groups: FV - Fluoride Varnish (Duraphat); FV+etch - Fluoride Varnish (Duraphat) after enamel etching with 37% phosphoric acid; or RI - Resin Infiltration system (Icon). Opacities were monitored for 18 months. The primary outcome was the loss of integrity due to post-eruptive enamel breakdown (PEB). Covariables included sex, age, DMFT index, opacity colour, plaque index, number of MIH-affected teeth, and number of MIH-affected surfaces. Fisher's Exact was used to test the association of treatments with PEB, the Kaplan-Meyer method analysed the survival rates and Cox-regression determined which covariables would predict failure (α=0.05).

RESULTS

From a total of 235 teeth, the PEB rate for RI (6.1%) was significantly lower (p<0.05) than FV (17.9%; OR 3.0, 95%CI 1.07, 8.48) and FV+etch (17.3%; OR 3.1, 95%CI 1.13, 8.73). DMFT index >3, brown opacities, cusp involvement, and age between 6-8 years predicted PEB (p<0.05).

CONCLUSIONS

Resin infiltration positively influenced the structural integrity maintenance of MIH-affected teeth by decreasing the risk of enamel breakdown over18 months follow-up. Registry of Clinical Trials (RBR-8wwk3n).

CLINICAL RELEVANCE

Resin infiltration proved to be a more efficacious intervention to maintain the structural integrity of MIH-affected teeth than fluoride varnish therapies.

Knowledge and Management of First Permanent Molars with Enamel Hypomineralization among Dentists and Orthodontists

Purpose: Molar Incisor Hypomineralization (MIH) is a developmental enamel anomaly of systemic origin affecting the first permanent molars and often the permanent incisors. Despite MIH being a prevalent anomaly, its diagnosis and management are challenging for practitioners; including poor anesthesia, failure of restorations, rapid enamel breakdown, poor resin adhesion, and related child anxiety. This study aimed to evaluate knowledge regarding and management of MIH amongst orthodontists and dentists. Study design: The study was performed from March to September 2017 and included 336 dentists and 32 orthodontists. Questionnaires comprised questions on MIH diagnosis, socio-demographic characteristics of the subjects, and photographs of a case of MIH with related questions regarding management. Results: Our results showed that 48% of dentists and 25% of orthodontists misdiagnosed MIH; with misdiagnosis associated with graduation prior to 1986 (p < 0.001). Amongst dentists, 59% applied a fluoridated product and 34% applied fissure sealants in the case of moderate MIH. The application of fluoride was associated with graduation after 1986 (p < 0.0001).Conclusion: Large disparities about knowledge and management of MIH exist between dental practitioners in France. Education regarding diagnosis and management of MIH is necessary.

Effect of Resin Infiltration Technique on Improving Surface Hardness of Enamel Lesions: A Systematic Review and Meta-analysis

OBJECTIVE

White spot lesion (WSL) is recognized as the first clinical sign of enamel caries; it is a very critical phase because it can be prevented from progression to frank caries by changing the surrounding destructive environment. The present study was undertaken to systematically review the effect of resin infiltration (RI) technique on surface hardness (SH) of WSL.

METHODS

Five electronic databases were searched with proper key words. Related titles and abstracts, up to October 2018, were screened, selected, and subjected to quality assessments. After collecting data, meta-analyses were carried out to compare the effect of RI with untreated WSL and sound enamel by using the STATA software.

RESULTS

A total of 4567 articles were included in the study after initial search. Finally, 10 studies were reliable enough in methodology to be included in the study. Metadata analyses, carried out on 7 studies that compared SH of RI group with untreated samples, showed a significant increase in SH with 3.66 mean difference (95% confidence interval = 2.56‒4.77, Q value = 36.07, I² = 83.4%). However, meta-analysis on 4 studies that compared SH of RI with sound enamel showed a significant decrease in SH with -2.35 overall mean difference (95% confidence interval = -3.91-0.98, P = .00, Q value = 31.75, I² = 90.6%).

CONCLUSION

The RI technique can enhance SH of WSL; however, regaining the SH of RI-treated WSLs similar to sound enamel is doubtful. Application of RI is more effective than other methods, including application of fluoride, enamel pro-varnish, adhesive, and colloidal silica infiltration for enhancing SH of WSLs.

Testing the Clinical Applicability of Resin Infiltration of Developmental Enamel Hypomineralization Lesions Using an In Vitro Model

Aim

The aim of this study is to investigate the penetration abilities of a commercially available low-viscosity resin infiltrant into developmentally hypomineralized teeth in vitro.

Materials and methods

Four extracted third molars of a 17-year-old patient with signs of developmental enamel hypomineralization (discoloration, increased opacity, and surface roughness) were infiltrated with a low-viscosity resin mixed with a fluorescent dye, according to the manufacturer's standard protocol. Four extracted molars with sound enamel or showing only initial fissure caries were used as a control group. Specimens were embedded in polymethylmethacrylate, and grindings were prepared. High-resolution projectional radiography of the grindings was performed, and, for one specimen, quantitative micro-computed tomography was used to measure hydroxyapatite density in enamel and dentin lesions. After decalcification, the grindings were examined by reflected bright-field microscopy, wide-field fluorescence microscopy, and confocal laser scanning microscopy. Fluorescence micrographs were superimposed on the radiographs and analyzed correlatively.

Results

The pattern of hypo-/demineralization in enamel and dentin in developmentally hypomineralized teeth showed a good congruence with the pattern of resin infiltration. Cavitations and dentin tubules up to a depth of 2 mm beyond cavitations were filled by the infiltrant. In control teeth, the penetration of the infiltrant was limited to decalcified enamel areas (initial fissure caries).

Conclusions

In vitro infiltration of developmentally hypomineralized enamel was successful.

Clinical significance

Resin infiltration might be considered as a routine procedure in the treatment of developmentally hypomineralized teeth. Further investigations with higher sample sizes, different degrees of severity, different stages of lesion extension, and modified treatment protocols are necessary.

How to cite this article

Schnabl D, Dudasne-Orosz V, et al. Testing the Clinical Applicability of Resin Infiltration of Developmental Enamel Hypomineralization Lesions Using an In Vitro Model. Int J Clin Pediatr Dent 2019;12(2):126-132.

Molar incisor hypomineralisation (MIH) - an overview

Recent data indicates that molar-incisor hypomineralisation (MIH) is a frequently - encountered dental condition worldwide. The condition could be associated with dental complications that might affect patients' quality of life as well as create treatment challenges to dentists. The affected teeth are more prone to caries and post-eruptive enamel breakdown, therefore, it is believed that this condition might be responsible for a substantial proportion of childhood caries since the condition has high prevalence. MIH is common, and as such it should be diagnosed and managed in primary care wherever possible. Early diagnosis can lead to more effective and conservative management. This article aims to highlight different aspects related to MIH, from its prevalence to treatment options in young patients.

Efficacy of 4-year treatment of icon infiltration resin on postorthodontic white spot lesions

White spot lesions are defined as enamel surface and sub surface demineralisation, although these lesions can be reversed and do not form cavities. Infiltration using fluid resin proved to be a valid micro-invasive alternative compared with traditional conservative therapy. This has allowed treatment without any trauma (no use of local anaesthesia and cavity preparation) of numerous lesions in only one session with stable clinical (mechanical stability, enamel hardness, conservation of sound tissue) and aesthetic results (disappearance of lesions) over the time. The present report evaluates the effectiveness of Icon infiltration resin on postorthodontic white spots at 6 months, 1 and 4 years.

Microhardness and Penetration of Artificial White Spot Lesions Treated with Resin or Colloidal Silica Infiltration

INTRODUCTION

Infiltration of early enamel lesions by materials having remineralizing capacity seems to improve aesthetics and arrests caries progression.

AIM

To evaluate and compare the surface microhardness and penetration depth of a low viscosity resin and colloidal silica nanoparticle infiltrates into artificially created white spot lesions.

MATERIALS AND METHODS

Forty extracted human central incisors were embedded in acrylic resin blocks exposing the labial surfaces of the crowns. The specimens were immersed in demineralizing solution for 96 hours to create white spot lesions on labial surfaces. The samples were then divided into two groups (n=20 each), where in Group 1-resin infiltration (ICON DMG, Hamburg, Germany) and Group 2-colloidal silica infiltration (Arrow Fine chemicals, Rajkot, Gujarat, India) was done. Samples were subjected to vicker's microhardness testing at baseline, after demineralization and after treatment with resin or colloidal silica infiltrates. Then, the crowns were sectioned longitudinally and penetration depth of the infiltrants was measured using confocal laser scanning microscope and compared the readings to lesion depth. All the collected data was subjected to statistical analysis using t-test.

RESULTS

Resin infiltration group showed significantly greater increase in microhardness compared to colloidal silica infiltration (p=0.001). The percentage of penetration of the resin group was 67.14% and that of colloidal silica group was 54.53% indicating significant difference between the two.

CONCLUSION

Resin infiltrates performed better in regaining the baseline microhardness and penetrating deep into the porous white spot lesions, when compared to colloidal silica infiltrates.