A scoping review of the influence of clinical contaminants on bond strength in direct adhesive restorative procedures

OBJECTIVE

Clinical contamination during direct adhesive restorative procedures can affect various adhesive interfaces differently and contribute to bulk failure of the restorations. This review aims to summarise the current knowledge on the influence of a variety of clinical contaminants on the bond strength at various adhesive interfaces during adhesive restorative procedures and identify gaps in the literature for future research.

DATA AND SOURCES

An electronic database search was performed in PubMed and EMBASE to identify articles that investigated the influence of contaminants on direct restorative bonding procedures. A data-charting form was developed by two researchers to capture the key characteristics of each eligible study.

STUDY SELECTION

The initial search yielded 1,428 articles. Fifty-seven articles published between 1 Jan 2007 and 25 Oct 2023 were included in the final review. Thirty-three of the articles examined the influence of saliva contamination, twelve articles examined the influence of blood contamination, and twenty-five articles examined the influence of other contaminants.

CONCLUSION

Saliva contamination exerted less influence on the decrease in bond strength when self-etch systems were used, compared to when etch-and-rinse systems were used. Blood contamination adversely affected the bond strength at the interface between resin composite and dentine, and resin composite and resin-modified glass ionomer cement. Treating contaminated surfaces with water spray for 10-30 s followed by air drying could be effective in recovering bond strength following saliva and blood contamination.

CLINICAL SIGNIFICANCE

This scoping review provides a valuable overview of the range of potential clinical contaminants that can influence the bond strength between different interfaces in direct adhesive restorative procedures. Additionally, it identifies potential decontamination protocols that can be followed to restore and enhance bond strength.

A Comparison of the Enamel Remineralisation Potential of Self-Assembling Peptides

BACKGROUND

The aim of this research was to compare the efficacy of the remineralising potential of self-assembling peptides (SAPs): Curodont Repair (P11-4), P26, and leucine-rich amelogenin peptides (LRAP) with the standard 5% NaF varnish (Duraphat) on early enamel caries lesions (EECLs).

METHODS

A demineralising solution (DS) was used to create artificial EECLs in human dental enamel specimens, which were randomly allocated to treatment groups: P11-4; P26 solution; LRAP solution; 5% NaF varnish; and deionised water (DIW). Each specimen was subjected to 8 days of pH cycling. Specimens from each test group were subjected to microcomputed tomography (micro-CT) and nanomechanical testing to assess mineral density (MD), hardness (H), and elastic modulus (EM) properties of sound, demineralised, and treated enamel.

RESULTS

The mean MD percentage gain was highest in the P26 and P11-4 groups, followed by the LRAP, 5% NaF varnish, and DIW groups. There were statistically significant differences amongst groups. In the outer layer of EECLs, the EM and H were highest in P26 and P11-4 groups, followed by the LRAP and 5% NaF varnish. In the inner layer of EECLs, the EM and H were highest in P11-4 and P26 groups, indicative of enhanced penetration and remineralisation of the deeper parts of the artificial EECLs.

CONCLUSIONS

P26 and P11-4 SAPs are more effective than 5% NaF varnish in remineralising the depth of EECLs.

Remineralization potential of dentifrices with calcium sodium phosphosilicate and functionalized tri-calcium phosphate in the deeper incipient carious lesions: An in vitro study

OBJECTIVES

This study evaluated the remineralization potential of calcium sodium phosphosilicate and functionalized tri-calcium phosphate (f-TCP) dentifrices in deeper incipient carious lesions (ICLs).

MATERIALS AND METHODS

Artificial ICLs were created by placing premolars into demineralizing solutions. Teeth were randomly assigned into four groups: calcium sodium phosphosilicate (Group 1), f-TCP (Group 2), 1450 ppm fluoride (Group 3), and distilled water (Group 4), which were subjected to 10-day pH cycling. Mineral density (MD) was assessed using microcomputed tomography (Micro-CT), while hardness (H) and elastic modulus (EM) were assessed using nanomechanical testing.

RESULTS

MD % gain was higher in Groups 1-3 than in Group 4. In addition, Groups 1 and 2 exhibited significantly higher MD % gain than Group 3. Also, Groups 1-3 showed significantly higher EM and H values than Group 4 in the outer enamel area; yet, Groups 1 and 2 displayed significantly higher EM and H values than Groups 3 and 4 in the inner enamel.

CONCLUSIONS

The MD, EM, and H of ICLs significantly increased with the addition of calcium sodium phosphosilicate or f-TCP to fluoridated dentifrices compared to standard fluoride dentifrices. The added active ingredients remineralized the deeper parts of the ICLs, while remineralization at the lesion surface was similar between tested dentifrices.

Combined effect of a bioinspired self-assembling peptide and fluoride varnish on remineralisation of artificial early enamel caries lesion: an in vitro study

INTRODUCTION

This study aimed to investigate the remineralisation effect of combined use of a bioinspired self-assembling peptide (P26) and fluoride varnish on artificial early enamel caries lesions.

METHODS

Bovine enamel blocks with artificial early enamel caries lesions were prepared. The blocks were randomly allocated to four experimental groups to receive following treatments: A. P26 + fluoride varnish, B. P26, C. Fluoride varnish and D. Distilled water (negative control). The treated blocks were subjected to pH cycling. Enamel blocks were collected at time points of 7 days (d7) and 21 days (d21). The mineral gain, elemental analysis and crystal characteristics of the caries lesion were assessed by micro-computed tomography, scanning electron microscopy with energy dispersive X-ray and X-ray diffraction (XRD), respectively.

RESULTS

The meanstandard deviation of mineral gain of Group A to D were (17.44.2) %, (10.72.2) %, (10.11.2) % and (6.80.5,) % at d7 respectively, and (15.22.6) %, (8.73.1) %, (9.71.2) % and (7.82.3) % at d21 respectively. A significant higher mineral gain was observed in Group A when compared to other groups at both d7 and d21 (p <0.05). The calcium to phosphate ratio remained consistent across all groups, ranging between 1.2-1.4. XRD analysis indicated that crystal composition on the surfaces was apatite for all groups.

CONCLUSION

In conclusion, the present study provided a first indication of better remineralisation effects of the combined use of the bioinspired self-assembling peptide P26 and fluoride varnish compared to the effects of the respective individual uses of P26 or fluoride varnish.

The Influence of Saliva and Blood Contamination on Bonding Between Resin-modified Glass Ionomer Cements and Resin Composite

OBJECTIVE

To investigate the influence of blood and saliva contamination on the microshear bond strength (μSBS) between resin-modified glass ionomer cement (RMGIC) and resin composite (RC).

METHODS AND MATERIALS

Eighty RMGIC discs were allocated into four groups (n=20). Group 1 received universal dental adhesive application in a self-etch mode followed by a build-up with RC. Group 2 received saliva as a contaminant, Group 3 received blood as a contaminant, Group 4 received a 1:1 blood-saliva mixture as a contaminant. Specimens from Groups 2, 3, and 4 were submerged into their respective contaminants for 15 seconds and dried prior to the adhesive application, followed by the protocol for Group 1. All specimens were stored in distilled water for 24 hours. Subsequently, the bonded specimens were subjected to μSBS testing using a universal testing machine. Failure mode of the debonded RMGIC surfaces was examined using scanning electron microscopy.

RESULTS

The μSBS from groups 1-4 were 10.76 ± 3.03 MPa, 9.36 ± 2.54 MPa, 6.55 ± 1.67 MPa and 8.42 ± 2.79 MPa, respectively. Contamination by blood and blood-saliva significantly decreased the μSBS (p<0.001, p=0.029). Saliva contamination alone had no statistically significant effect on the μSBS (p=0.524). A statistically significant difference in the mode of failure was detected between the experimental groups (p=0.012).

CONCLUSION

Saliva contamination has no influence on μSBS between RMGIC and RC when it is dried thoroughly, while blood and blood-saliva contamination reduced μSBS between RMGIC and RC even when dried thoroughly.

Potential Beneficial Effects of Hydroxyapatite Nanoparticles on Caries Lesions In Vitro-A Review of the Literature

Dental caries is one of the most common human diseases which can occur in both primary and permanent dentitions throughout the life of an individual. Hydroxyapatite is the major inorganic component of human teeth, consequently, nanosized hydroxyapatite (nHAP) has recently attracted researchers' attention due to its unique properties and potential for caries management. This article provides a contemporary review of the potential beneficial effects of nHAP on caries lesions demonstrated in in vitro studies. Data showed that nHAP has potential to promote mineralization in initial caries, by being incorporated into the porous tooth structure, which resulted from the caries process, and subsequently increased mineral content and hardness. Notably, it is the particle size of nHAP which plays an important role in the mineralization process. Antimicrobial effects of nHAP can also be achieved by metal substitution in nHAP. Dual action property (mineralizing and antimicrobial) and enhanced chemical stability and bioactivity of nHAP can potentially be obtained using metal-substituted fluorhydroxyapatite nanoparticles. This provides a promising synergistic strategy which should be explored in further clinical research to enable the development of dental therapeutics for use in the treatment and management of caries.

A comparative study of two chemical models for creating subsurface caries lesions on aprismatic and prismatic enamel

PURPOSE

To investigate the mineral density and lesion depth of artificial caries lesions on aprismatic enamel and prismatic enamel created by lactic acid and acetic acid buffers.

METHODS

Forty bovine enamel blocks were allocated to: aprismatic enamel (Group A) and prismatic enamel (Group C) in acetic acid buffer for 192 h and aprismatic enamel (Group B) and prismatic enamel (Group D) in lactic acid buffer for 96 h. The mineral loss and lesion depth were measured using micro-computed tomography.

RESULTS

A significant difference (P = 0.01) was observed in the mineral loss (%) in the lesions on aprismatic enamel and prismatic enamel treated with lactic acid buffer while no significant difference (P = 0.51) was observed in the mineral loss (%) in the lesions on aprismatic enamel and prismatic enamel treated with acetic acid buffer. No significant difference was noted in the mean lesion depth of lesions on aprismatic enamel and prismatic enamel treated with acetic acid and lactic acid buffers (P > 0.05).

CONCLUSION

Aprismatic enamel and prismatic enamel have similar mineral loss in acetic acid while prismatic enamel showed more mineral loss compared to aprismatic enamel in lactic acid.

Caries-preventive effectiveness of two different fluoride varnishes: A randomised clinical trial in patients with multi-bracketed fixed orthodontic appliances

BACKGROUND

Patients with multi-bracketed fixed orthodontic appliances are at a higher risk of developing enamel demineralisation.

AIM

To compare the efficacy of the quarterly application of two varnishes in preventing white spot lesions (WSLs) during multi-bracketed fixed orthodontic treatment.

DESIGN

Ninety-nine patients were randomly allocated into three intervention groups: Group A-standard oral hygiene instructions (OHI); Group B-5% sodium fluoride (NaF) varnish with standard OHI; and Group C-NaF plus tricalcium phosphate varnish with standard OHI. The outcome was assessed at 6-monthly intervals using a quantitative laser fluorescence device, clinical evaluation and photographic evaluation on six maxillary anterior teeth. A logistic regression model using generalised estimating equations with the intervention group, time and their interaction was used to compare the occurrence of WSLs, whereas the independent-samples Kruskal-Wallis test was used to compare the means of fluorescent values among different groups at p = .05.

RESULTS

Generalised estimating equations (with intervention and time as predictors) showed that only the effect of time was found to be significant (p < .001), whereas there was no significant difference among the three intervention groups (p = .305) using clinical assessment or photographic assessment (p = .599). At the 18-month follow-up, sodium fluoride (NaF) varnish with standard OHI was shown to reduce the odds of WSLs by 55% (p = .200), and NaF plus tricalcium phosphate varnish with standard OHI by 42% (p = .327).

CONCLUSION

The study failed to demonstrate that the quarterly application of both the study varnishes with OHI provided additional benefits compared with standard OHI alone in preventing WSLs, taking the effect of time of follow-up into consideration. There were higher odds of developing WSLs with an increased duration of orthodontic treatment.

Does Early Childhood Caries Increase Caries Development among School Children and Adolescents? A Systematic Review and Meta-Analysis

The aim of this paper is to systematically review the literature to determine whether early childhood caries (ECC) is significantly associated with caries development in permanent teeth among school children and adolescents, and to identify the association of other risk factors over 24 months. A systematic literature search was performed in four electronic databases and via a manual search from inception to 28 July 2022. Independent study selection and screening, data extraction, evaluation of risk of bias using ROBINS-I tool and certainty of evidence with GRADE were performed. Ten cohort studies were included, all of which identified that ECC significantly increased the risk of caries in permanent teeth. Meta-analysis suggested children with ECC were three times more likely to develop caries in their permanent teeth (OR, 3.22; 95% CI 2.80, 3.71; p < 0.001), especially when the lesions were in primary molars and progressed to dentine. However, the certainty of evidence was substantially compromised by serious risk of bias and inconsistency between studies. There were inconsistent findings between socioeconomic or behavioural factors on caries development, which could not be pooled for meta-analyses. ECC significantly increases the likelihood of caries development in permanent teeth. Evidence on the association of socioeconomic and oral health behavioural factors is weak.

Prevention of demineralization during multi-bracketed fixed orthodontic treatment: An overview of systematic reviews

BACKGROUND

Demineralization during multi-bracketed fixed orthodontic treatment is a well-known problem.

AIM

To systematically evaluate the evidence for the prevention of enamel demineralization during multi-bracketed fixed orthodontic treatment.

DESIGN

Systematic reviews (with or without meta-analysis) that have appraised the primary studies on the prevention of demineralization during multi-bracketed fixed orthodontic treatment were searched systematically and included as per pre-defined eligibility criteria. The risk of bias of the included reviews was assessed by two authors using the ROBIS tool and AMSTAR-2 tool.

RESULTS

Twenty-nine reviews conducted on 128 exclusive primary studies were included for the present overview; 23 of these reviews were assessed to be of a high risk of overall bias, 5 were of low risk, and 1 review was of unclear risk of bias.

CONCLUSIONS

Predominantly, the published reviews have focused on fluorides, whereas some reviews have also studied the role of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), reminder therapy, lasers, and sealants. Professional fluorides, sealants, reminder therapy, and lasers might be valuable interventions to prevent demineralization during orthodontic treatment based on the conclusions of reviews with high quality; however, further studies are required to elucidate the role of CPP-ACP, chlorhexidine varnish, and powered toothbrushes.

Validation of clinical photography and a laser fluorescence device for assessment of enamel demineralization during multi-bracketed fixed orthodontic treatment

AIM

To compare the validity of DIAGNOdent pen™ 2190 and clinical photographs in the diagnosis (presence or absence) and assessment of white spot lesions (WSLs) during multi-bracketed fixed orthodontic treatment.

METHODS

A total of 1607 readings from 99 patients were obtained using DIAGNOdent pen™ 2190, clinical photographs, and visual assessment criteria to assess WSLs at 6 -, 12- and 18 months after bonding of brackets. Receiver operating characteristic curves were constructed, and areas under the curve (AUC) were calculated to assess the presence or absence of WSLs and distinguish the severity of WSLs as slight or severe. Sensitivities, specificities, and AUC were calculated for outcomes at an alpha of 0.05 and 95% confidence intervals (CIs).

RESULTS

The values of sensitivity and specificity of DIAGNOdent pen™ 2190 were found to be 0.78 and 0.83, respectively, to distinguish presence/absence of WSLs with good accuracy (AUC= 0.855; 95% CI: 0.820-0.889) and for digital photographs, accuracy was excellent (AUC= 0.973, 95% CI: 0.956-0.991) with sensitivity and specificity of 0.96 and 0.99, respectively. However, the accuracy of DIAGNOdent pen™ 2190 was poor (AUC= 0.543, 95% CI: 0.418-0.668) in delineating slight and severe WSLs with a sensitivity of 0.31 and specificity of 0.83; while the values of sensitivity and specificity for distinguishing slight or severe lesions for clinical photographs were 0.96 and 0.99, respectively with excellent accuracy (AUC=0.978, 95% CI: 0.936-1.000).

CONCLUSIONS

Clinical photographs had better validity than DIAGNOdent pen™ 2190 in diagnosis and assessment of severity of demineralized lesions during multi-bracketed fixed orthodontic treatment.

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.

Bonding Universal Dental Adhesive to Developmentally Hypomineralised Enamel

PURPOSE

To investigate the effect of pretreatment protocols involving Papacarie Duo gel and Scotchbond Universal (SU) on the microshear bond strength (µSBS) of resin composite (RC) to hypomineralised enamel (HE).

MATERIALS AND METHODS

Specimens of normal enamel (NE) and HE were derived from extracted hypomineralised first permanent molars (FPMs). Based on the colour of demarcated opacities, HE specimens were classified as creamy/white (CW) or yellow/brown (YB). The specimens were randomly allocated into eight groups (n = 20). Each group involved pretreatment with Papacarie Duo gel or no pretreatment, and SU applied in etch-and-rinse (E&R) or self-etch (SE) mode. All specimens were bonded with RC and subjected to µSBS testing. Failure modes were analysed using an optical microscope and SEM.

RESULTS

Comparing NE with HE, the following factors were found to be significant (p < 0.001): type of enamel substrate, deproteinising pretreatment, and etching mode. Comparing CW HE with YB HE, a significant interaction between "deproteinising pretreatment" and "etching mode" was demonstrated (p = 0.028). When subjected to the concurrent use of Papacarie Duo gel and phosphoric acid etching, HE specimens showed a significant increase in µSBS (p < 0.001).

CONCLUSION

Deproteinising pretreatment using Papacarie Duo gel followed by the application of SU in E&R mode led to increased µSBS of resin composite to HE.

Effectiveness of oral health education methods on oral hygiene in children and adolescents with visual impairment: A systematic review

BACKGROUND

Conventional methods of oral health education (OHE) are not suitable for children with visual impairment, as these methods usually involve visual demonstration with models or plaque-disclosing dyes.

AIM

To systematically review the literature to support the best approach for providing OHE to children and adolescents with visual impairment.

DESIGN

A systematic search of five electronic databases and grey literature was conducted. Randomized controlled trials that compared different OHE methods in children and adolescents with visual impairment were included. The Cochrane risk-of-bias tool (RoB 2) was used for the risk-of-bias assessment. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework was used to determine the certainty of evidence.

RESULTS

Nine randomized controlled trials with a total of 804 participants were included in this review. Seven OHE methods were compared. Seven studies were assessed to be at high risk of bias, one study was assessed to have some concerns, and one study was assessed to be at low risk of bias. The overall certainty of evidence was very low according to GRADE.

CONCLUSION

There was insufficient evidence to recommend a particular method of OHE as more effective in improving the oral hygiene of children with visual impairment, but combination methods may show similar or better results.

Knowledge of dental enamel defects amongst undergraduate dental students-a cross-sectional survey

INTRODUCTION/OBJECTIVES

Enamel defects are disturbances in the quantity or quality of enamel, due to disruption or damage to the enamel organ during amelogenesis. The correct diagnosis of enamel defects is critical as diverse management options could be required for different conditions. Difficulties in diagnosis can happen, because these defects may have similar clinical presentations. This study evaluated the diagnostic skills in enamel defects of dental students of a prominent Australasian school.

METHODS

A questionnaire consisting of clinical photographs of the affected teeth/dentition in multiple views and four standardised questions for each case of enamel defect were given to Year 4 and Year 5 students.

RESULTS

Localised/Chronological Hypoplasia had the lowest percentage of correct diagnosis (20.5%), whilst Enamel White Spot Lesions (EWSLs) had the highest (85%). Localised/Chronological Hypoplasia had the lowest aetiology score (20.5%), and the highest was obtained for EWSLs (85%). In regard to which question to ask to gain insight into the conditions, Enamel Hypomineralisation/MIH had the lowest score for both Year 4 and Year 5 respondents (35.4% and 21.3%). Most respondents agreed more teaching in this topic was needed, with further clinical sessions to observe the enamel defects, workshops/seminars, lectures and student-driven presentations suggested.

CONCLUSION

Final-year dental students showed variable knowledge in diagnosis, aetiology and clinical management of enamel defects. Further didactic and clinical teaching should be incorporated in the undergraduate curriculum on this topic .

Glass Ionomer Sealant versus Fluoride Varnish Application to Prevent Occlusal Caries in Primary Second Molars among Preschool Children: A Randomized Controlled Trial

Fissure sealant is a recommended preventive measure on permanent molars, but its efficacy on primary molars in preschool children is still in doubt. Sodium fluoride varnish (NaFV) enhances remineralization and is effective in preventing caries in smooth surfaces, but limited information is available regarding its use on occlusal surfaces of primary molars. The present study aimed to compare the efficacy of glass ionomer sealant (GIS) versus topical application of 5% NaFV in preventing and arresting occlusal caries in primary second molars among preschool children. One calibrated examiner examined children aged 3-4 years for visible plaque index (VPI), decayed-missing-filled primary surface (dmfs) index, and extent of carious lesions by the International Caries Detection and Assessment System (ICDAS). Subjects with 1 or more primary second molars that were sound or with incipient lesions (ICDAS 0-1), with distinct visual enamel changes (ICDAS 2), or with localized enamel breakdown (ICDAS 3) were recruited. The children were randomly assigned to either NaFV group - application of 5% NaFV at 3-monthly intervals or GIS group - 1 single placement of GIS. A parental questionnaire was used to collect information on the children's sociodemographic background and oral health-related habits. Two blinded examiners conducted clinical examinations after 6 and 12 months to evaluate the development of occlusal caries and the retention of GIS. Negative binomial regression using generalized estimating equations was employed to adjust for the clustering effect and evaluate the influence of selected variables on the development of occlusal caries into dentin at 12 months. A total of 323 children with 1,159 primary second molars received the respective preventive measures at baseline. At 12 months, 280 children with 989 molars were evaluated. Caries had developed or progressed into dentin in 7.8% and 8.0% of the molars in the NaFV and GIS groups, respectively, with no significant difference between the groups (p = 0.913). The overall retention rates of GIS were 24.6% and 13.5% at 6 and 12 months, respectively. Regression analyses showed only baseline caries experience, and an ICDAS code had a significant association with occlusal caries progression. Quarterly NaFV application and single GIS placement showed similar effectiveness in the prevention of occlusal caries development among preschool children.

Combined effect of arginine and fluoride on the growth of Lactobacillus rhamnosus GG

The objectives of the in vitro study were: (1) to investigate the effect of combining L-arginine (Arg) and NaF on the growth of Lactobacillus rhamnosus GG (LRG); and (2) to identify an optimum synergistic concentration for the synbiotic (Arg + LRG)-fluoride (SF) therapy. 1% Arg + 2000-ppm NaF (A-SF) and 2% Arg + 2000-ppm NaF (B-SF) demonstrated antagonism against LRG (FIC > 4.0). Both XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and WST-8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt) assays showed that A-SF and B-SF enhanced the growth of LRG when compared to 2000-ppm NaF and LRG control. Colony forming units, bacterial weight, and biofilm thickness of A-SF and B-SF were significantly higher than 2000-ppm NaF and LRG control. Biofilm imaging depicted that 2000-ppm NaF inhibited biofilm formation; while 1%/2% Arg, A-SF, and B-SF increased biofilm growth of LRG. Lactic acid formation was the lowest for 2000-ppm NaF, followed by A-SF and then B-SF. The SF buffer potential after 24 h was the highest for B-SF, and then A-SF. Biofilm pH for B-SF was closest to neutral. Fluoride, Arg and LRG bioavailability remained unaffected in B-SF. The relative gene expression for arcA, argG, and argH was significantly higher for B-SF than the respective controls. In conclusion, combining 2% Arg, 2000-ppm NaF, and LRG provides an optimum synbiotic-fluoride synergism.

Physicochemical Characteristics of Arginine Enriched NaF Varnish: An In Vitro Study

The in vitro study objectives were to investigate the effect of arginine (Arg) incorporation in a 5% sodium fluoride (NaF) varnish on its physical and chemical properties including F/Arg release. Six experimental formulations were prepared with L-arginine (L-Arg) and L-arginine monohydrochloride at 2%, 4%, and 8% w/v in a 5% NaF varnish, which served as a control. The varnishes were subjected to assessments for adhesion, viscosity, and NaF extraction. Molecular dynamics were simulated to identify post-dynamics total energy for NaF=Arg/Arg>NaF/Arg<NaF concentrations. The Arg/F varnish release profiles were determined in polyacrylic lactate buffer (pH-4.5; 7 days) and artificial saliva (pH-7; 1 h, 24 h, and 12 weeks). Incorporation of L-Arg in NaF varnish significantly influences physical properties ameliorating retention (p < 0.001). L-Arg in NaF varnish institutes the Arg-F complex. Molecular dynamics suggests that NaF>Arg concentration denotes the stabilized environment compared to NaF<Arg (p < 0.001). The 2% Arg-NaF exhibits periodic perennial Arg/F release and shows significantly higher integrated mean F release than NaF (p < 0.001). Incorporating 2% L-arginine in 5% NaF varnish improves its physical properties and renders a stable matrix with enduring higher F/Arg release than control.

Inter-method reliability for determining total and soluble fluorides in child low-fluoride formula dentifrices

The study aimed to compare three methods for determining total (TF) and total soluble fluorides (TSF) in 5 child formula dentifrices (CFD) using Inter-method reliability (IMR) statistical approach. The methods were direct acid-hydrolysis (DM), the least-time-consuming method; Modified direct acid-hydrolysis with standard-addition method (MDM), ISO 19448:2018 method; and modified Taves acid-HMDS diffusion analysis (TAD), the claimed gold standard method. A significant difference in the mean difference was observed for all methods at all levels (p < 0.001), except DM and TAD for TF (p = 0.622). A proportional bias was discerned in the agreement distribution between DM and TAD for TF (p < 0.001). The ICC analysis identified significant reliability between all measurements, irrespective of the model, measure, and fluoride type (p < 0.001). For TF and TSF, the IMR between DM and TAD was lower than MDM and TAD for consistency/absolute agreement reliability at single/average measures. The reliability measure for DM and MDM was higher than MDM and TAD for TSF, but was lower than MDM and TAD for TF. The ICC measure for DM-TAD was significantly lower than DM-MDM and MDM-TAD (p < 0.05). The ISO 19448:2018 MDM is a reliable test that can be used as an alternative to TAD/DM for determining TF/TSF in CFD.

Enamel remineralization potential of arginine-fluoride varnish in a multi-species bacterial pH-cycling model

OBJECTIVES

To examine the enamel fluoride uptake and remineralization potential of arginine-fluoride (Arg-NaF) varnishes in a simulated clinical condition using a multi-species bacterial pH-cycling model.

METHODS

L-Arginine (at 1 %, 2 %, and 4 % by wt.) was incorporated in a 5 % NaF varnish. Experimental and control groups were: 1 % Arg-NaF; 2 % Arg-NaF; 4 % Arg-NaF; NaF and no treatment. Artificial incipient caries-like lesions were formed on 30 enamel specimen blocks (n = 6). The specimens underwent multi-species bacterial pH-cycling in an artificial mouth system using oral biofilm reactor for 72 h after treatment. The specimens were evaluated for mineral density using micro-CT, Ca/P ratio with SEM-EDX, enamel fluoride uptake (EFU) and plaque fluoride uptake (PFU).

RESULTS

Increasing concentrations of Arg in NaF varnish significantly increased the EFU of incipient caries-like lesions (p < 0.001). The PFU for 1 % Arg-NaF was significantly higher than 4 % Arg-NaF and the control NaF (p < 0.05). Post pH-cycling, Ca/P ratio with 1 %/2 % Arg-NaF was closest to hydroxyapatite (1.67). Mineral gain and % remineralization of 1 %/2 % Arg-NaF was significantly higher than the control NaF varnish (p < 0.05).

CONCLUSION

The prebiotic L-arginine (at 1 %/2 % by wt.) in a 5 % NaF varnish enhanced the enamel fluoride uptake and remineralization potential of the conventional 5 % NaF varnish.

CLINICAL SIGNIFICANCE

The Arg-NaF varnish addresses the limitations of fluorides on cariogenic biofilms. The Arg-NaF varnish appears a promising caries-preventive regimen that counters the pathogenic biofilms by Arg and promotes remineralization with fluorides. In high caries-risk patients, professional application of Arg-NaF varnish might aid to alleviate the global burden of dental caries.

Effectiveness of self-applied topical fluorides against enamel white spot lesions from multi-bracketed fixed orthodontic treatment: a systematic review

BACKGROUND

The regular use of fluoride dentifrices is quite practical, widespread and linked to global decline of dental caries. However, the role of self-applied topical fluorides in prevention and reversal of Enamel White Spot Lesions (EWSLs) during multi-bracketed fixed orthodontic treatment is not yet explored.

OBJECTIVE

To systematically appraise the current literature on the effectiveness of self-applied topical fluorides in the prevention and reversal of EWSLs occurring during multi-bracketed fixed orthodontic treatment.

SEARCH METHODS

Four electronic databases (Cochrane Library, Embase via Ovid, Medline via Ovid, and Scopus) and gray literature were searched using the broad MeSH terms and keywords.

SELECTION CRITERIA

Only randomized/quasi-randomized controlled clinical trials evaluating the effectiveness of self-applied fluorides in the prevention of EWSLs during multi-bracketed fixed orthodontic treatment or reversal of post-orthodontic EWSLs were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently screened for studies, extracted data and assessed the risk of bias using the Cochrane risk of bias tool 2.0. Due to substantial variations in the interventions, control groups, and the measurement of outcome among studies, quantitative synthesis could not be performed as planned.

RESULTS

Only three studies could be included in the present review; two of them assessing prevention of EWSLs and one addressing reversal of post-orthodontic EWSLs. One of the studies was judged to be of low risk of overall bias, whereas 2 studies were adjudged to be of high risk of overall bias because of deviations from intended interventions. The certainty of evidence about the role of self-applied fluorides in prevention and reversal of EWSLs was found to be of low quality; hence, our confidence in the effect estimate is limited, and future well-conducted trials might alter the effect estimates.

LIMITATIONS

The inclusion of only English literature and inability to perform quantitative synthesis due to a limited number of studies.

CONCLUSIONS AND IMPLICATIONS

Although the review did not confirm the effectiveness of self-applied fluorides in the reversal of EWSLs, it did partially substantiate the positive role of self-applied fluorides in the prevention of EWSLs occurring during multi-bracketed fixed orthodontic treatment. The review recommends the need for well-designed randomized controlled trials evaluating the effectiveness of self-applied fluorides on the prevention and reversal of EWSLs during multi-bracketed fixed orthodontic treatment.

REGISTRATION

PROSPERO database (Registration number: CRD42018108590) and is freely available at: http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42018108590.

FUNDING

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

A Scoping Review on Arginine in Caries Prevention

OBJECTIVES

Emerging science on arginine or arginine formulations has driven the need to examine the research in the field. The scoping study objectives were (1) to identify the extent, range, and type of evidence on the role of arginine or arginine formulations in caries prevention and (2) to explore the future scope of research on arginine-containing caries-preventive agents.

METHODS

A systematic search was performed in PubMed, Scopus, and Web of Science. In vitro studies, clinical trials, narrative reviews, systematic reviews and or meta-analysis, and umbrella reviews or meta-evaluation examining arginine or arginine formulations for caries prevention were included. The data-charting process involved extracting variables followed by evidence synthesis. Arginine variants investigated up to date were discussed to explore future scope of research.

RESULTS

Thirty-nine articles were included for review from 105 identified citations comprising of in vitro studies, clinical trials, and reviews. Most articles studied 1.5% arginine-fluoride toothpaste. Most studies were from Asia, followed by North America, with fewest studies from Europe and South America. Arginine or arginine formulations demonstrated a superior caries-preventive effect compared with their matched controls (including fluorides); however, the evidence is with high risk of bias. Until now, three arginine variants have been investigated with l-arginine monohydrochloride as the least explored variant.

CONCLUSIONS

The evidence on the caries-preventive effect of arginine or arginine formulations has a high risk of bias. High-quality clinical trials are needed to assess the caries-preventive potential of arginine in commercial formulations. The role of l-arginine monohydrochloride in caries prevention can further be explored by incorporating in self-applied and professionally applied caries-preventive agents.

Identification of Key Functional Motifs of Native Amelogenin Protein for Dental Enamel Remineralisation

Dental caries or tooth decay is a preventable and multifactorial disease that affects billions of people globally and is a particular concern in younger populations. This decay arises from acid demineralisation of tooth enamel resulting in mineral loss from the subsurface. The remineralisation of early enamel carious lesions could prevent the cavitation of teeth. The enamel protein amelogenin constitutes 90% of the total enamel matrix protein in teeth and plays a key role in the biomineralisation of tooth enamel. The physiological importance of amelogenin has led to the investigation of the possible development of amelogenin-derived biomimetics against dental caries. We herein review the literature on amelogenin, its primary and secondary structure, comparison to related species, and its’ in vivo processing to bioactive peptide fragments. The key structural motifs of amelogenin that enable enamel remineralisation are discussed. The presence of several motifs in the amelogenin structure (such as polyproline, N- and C-terminal domains and C-terminal orientation) were shown to play a critical role in the formation of particle shape during remineralization. Understanding the function/structure relationships of amelogenin can aid in the rational design of synthetic polypeptides for biomineralisation, halting enamel loss and leading to improved therapies for tooth decay.

Synbiotics in caries prevention: A scoping review

The scoping review aimed to examine the evidence on the role of synbiotics in caries prevention. PubMed, SCOPUS, and Web of Science databases search were performed. Any in vitro study, clinical trial, systematic review with/without meta-analysis, umbrella review/meta-evaluation, narrative review addressing the role of synbiotics in caries prevention were included in the scoping review. Data were extracted from the included studies using pre-approved registered protocol. Twenty-eight records were identified, of which 5 in vitro studies, 1 quasi-experimental clinical trial and 1 narrative review were included in the present review. No controlled clinical trials or systematic reviews on the role of synbiotics in caries prevention could be identified. Except 1, all in vitro studies examined the combined effect of saccharides and lactobacilli spp. as potential synbiotics on the growth of Streptococcus mutans. However, the proposed synbiotics in 4 in vitro studies either did not qualify or remained ambiguous of its eligibility as a potential synbiotic for caries prevention. One recent in vitro study explored the possibility of L-arginine and Lactobacillus rhamnosus GG synbiotic for caries prevention. The quasi-experimental clinical study without a control arm did not explicitly mention the intervention composition and thus, its synbiotic potential remains unclear. A narrative review highlighted the potential of combining arginine (prebiotic) with arginolytic bacteria (probiotic) as a synbiotic, which appears promising for caries prevention. The eligibility of the proposed synbiotics as a true synbiotic needs to be carefully addressed. Due to a lack of controlled clinical studies on synbiotics for caries prevention, evidence on their caries-preventive potential is weak. Future studies are needed to examine the combination of amino acids (esp. arginine) with probiotics as a potential synbiotic against cariogenic pathogens.

Antibacterial and mechanical properties of arginine-containing glass ionomer cements

OBJECTIVE

The study investigated the effect of incorporating l-arginine (Arg) in a glass ionomer cement (GIC) on its mechanical properties and antibacterial potential.

METHODS

Pre-determined proportions (1%, 2%, and 4% by wt.) of Arg were incorporated in GIC powder; while GIC without Arg served as control. The flexural strength, nanohardness, surface roughness, elemental analysis using SEM-EDX (n = 6) and F/Arg/Ca/Al/Si release in deionized water for 21 days were assessed. The antibacterial potential was evaluated in a multi-species biofilm model with Streptococcus mutans, Streptococcus sanguinis, Streptococcus gordonii, and Lactobacillus acidophilus for 72 h. Real-time qPCR was used to analyse biofilm bacterial concentrations. Propidium monoazide modification of real-time qPCR was performed to quantify viable/dead bacteria. The pH, lactic acid, ADS activity, and H₂O₂ metabolism were measured. Confocal microscopy was used to investigate the biofilm bacterial live/dead cells, density, and thickness.

RESULTS

There was no difference in flexural strength among the different groups (p > 0.05). No significant difference in nanohardness and surface roughness was observed between 4% Arg + GIC and control (p > 0.05). The 4% Arg + GIC showed significantly higher F/Arg/Al/Si release than the other groups (p < 0.05), reduced total bacterial concentration and growth inhibition of viable S. mutans and S. sanguinis (p < 0.05). Lactic acid formation for 4% Arg + GIC was significantly higher than 1% Arg + GIC (p < 0.05). The spent media pH of 4% Arg + GIC was higher than the other groups (p < 0.05), with proportionately lower ammonia and higher H₂O₂ released (p < 0.05).

SIGNIFICANCE

Addition of 4% l-arginine in GIC enhanced its antibacterial activity via a biofilm modulatory effect for microbial homeostasis, with no detrimental effect on its mechanical properties.

Effectiveness of Pit and Fissure Sealants for Preventing and Arresting Occlusal Caries in Primary Molars: A Systematic Review and Meta-Analysis

OBJECTIVE

The use of pit and fissure sealants have been well supported in permanent teeth, but no concrete evidence is available to support this procedure in primary molars. This review aims to systematically assess randomized controlled trials and summarize the evidence on the effectiveness of different sealants in prevention and arrest of the pit and fissure occlusal caries in primary molars of children.

MATERIALS AND METHODS

Four electronic databases were searched from inception to March 2018. Seven studies were included in the qualitative and quantitative syntheses. Two reviewers independently selected studies, extracted data, assessed risk of bias using the revised Cochrane risk of bias tool, and evaluated the certainty in the evidence adopting the Grading of Recommendations Assessment Development and Evaluation approach. Odds ratio and retention rate of different sealants were recalculated and analyzed.

RESULTS

This review identified no significant difference in the overall caries incidence and progression when evaluated over 24 months between (1) resin-based sealant (RBS) and glass ionomer sealants (GIS) or resin-modified GIS; (2) conventional and newly developed RBS; (3) autopolymerized and light-polymerized RBS; (4) RBS with topical fluoride application and topical fluoride alone; and (5) RBS with topical fluoride application and resin infiltration with topical fluoride application. The pooled estimates of the mean retention rates of RBS and GIS on primary molars over an 18-months period were 85.94% and 23.18%, respectively. The certainty in the evidence of each outcome was determined as low or very low mainly because of high risk of overall bias and imprecision.

CONCLUSION

There are currently insufficient well-controlled randomized controlled clinical trials to determine whether sealants are beneficial in preventing or arresting noncavitated occlusal caries in the primary molars.

Prevention of Demineralization Around Orthodontic Brackets Using Sealants: A Systematic Review and Meta-Analysis

Purpose: To evaluate the role of sealants in the prevention of enamel white spot lesions (EWSLs) around bonded orthodontic brackets. Methods: Eight databases and grey literature were searched for randomized or quasirandomized controlled clinical trials that assessed the placement of sealants around bonded brackets for the prevention of demineralization during fixed orthodontic treatment. Two reviewers independently selected studies, extracted data, assessed the risk of bias using Cochrane Risk of bias tool 2.0, and evaluated the certainty of evidence using the GRADE approach. Results: Eight clinical trials were included for qualitative synthesis; five of which assessed the outcome at debonding and hence were included for quantitative synthesis. Odds ratios (ORs) were calculated using the corrected Becker-Balagtas method. The OR of EWSLs in the sealants group versus the control group was found to be 0.69 (95 percent confidence interval [95% CI] equals 0.53, 0.89; P=.005) in the five included studies; however, after performing sensitivity analysis by excluding two studies with high risk of bias, the value was 0.68 (95% CI equals 0.41, 1.13; P=0.138). Conclusions: The certainty of evidence regarding the effectiveness of sealants in the prevention of the EWSLs was found to be moderate (downgraded because of the study limitations).

Remineralization Potential of Calcium and Phosphate-based Agents and Their Effects on Bonding of Orthodontic Brackets

PURPOSE

To compare the remineralization potential of Clinpro Tooth Crème (CTC C, 3M Oral Care) containing functionalized tricalcium phosphate (fTCP), Tooth Mousse (TM, GC) containing casein phosphopeptide amorphous calcium phosphate (CPP-ACP), and Tooth Mousse Plus (TMP, GC) containing casein phosphopeptide amorphous calcium phosphate with fluoride (CPP-ACPF) and their effects on the shear bond strength (SBS) of orthodontic brackets to enamel.

MATERIALS AND METHODS

In Part I of the study, 51 premolars were divided into 3 groups: 1: fTCP; 2: CPP-ACP; 3: CPP-ACPF. Artificial carious lesions were created and immersed in remineralizing solution for 30 days. Specimens were evaluated using Knoop microhardness and transverse microradiography. The percentage of surface hardness recovery (%SHR), change in lesion depth (∆LD), and mineral loss (∆∆Z) were analyzed using one-way ANOVA. In Part II of the study, 80 premolars were divided into 5 groups: A: brackets bonded to sound enamel; B: brackets bonded to demineralized enamel (DE); C-E: demineralized enamel immersed in remineralizing solution containing fTCP (group C), CPP-ACP (group D), or CPP-ACPF (group E) before bracket bonding. The SBS of half of the specimens were tested immediately, while the other half were tested after thermocycling. Data were analyzed using two-way ANOVA.

RESULTS

TMP showed significantly higher %SHR, ∆LD and ∆∆Z compared to the other groups (p < 0.05). Both control and TMP had the highest SBSs and demineralized enamel the lowest, irrespective of thermocycling. No significant difference in SBS was found between TM and TMP after thermocycling.

CONCLUSIONS

Tooth Mousse Plus achieved significant remineralization of artificial enamel carious lesions without adverse effect on shear bond strength of orthodontic brackets to remineralized enamel.

A comparison of visual identification of dental radiographic and nonradiographic images using eye tracking technology

Objectives

Eye tracking has been used in medical radiology to understand observers' gaze patterns during radiological diagnosis. This study examines the visual identification ability of junior hospital dental officers (JHDOs) and dental surgery assistants (DSAs) in radiographic and nonradiographic images using eye tracking technology and examines if there is a correlation.

Material and methods

Nine JHDOs and nine DSAs examined six radiographic images and 16 nonradiographic images using eye tracking. The areas of interest (AOIs) of the radiographic images were rated as easy, medium, and hard, and the nonradiographic images were categorized as pattern recognition, face recognition, and image comparison. The participants were required to identify and locate the AOIs. Data analysis of the two domains, entire slide and AOI, was conducted by evaluating the eye tracking metrics (ETM) and the performance outcomes. ETM consisted of six parameters, and performance outcomes consisted of four parameters.

Results

No significant differences were observed for ETMs for JHDOs and DSAs for both radiographic and nonradiographic images. The JHDOs showed significantly higher percentage in identifying AOIs than DSAs for all the radiographic images (72.7% vs. 36.4%, p = .004) and for the easy categorization of radiographic AOIs (85.7% vs. 42.9%, p = .012). JHDOs with higher correct identification percentage in face recognition had a shorter dwell time in AOIs.

Conclusions

Although no significant relation was observed between radiographic and nonradiographic images, there were some evidence that visual recognition skills may impact certain attributes of the visual search pattern in radiographic images.

The combined antimicrobial effect of arginine and fluoride toothpaste

The aim of the study was to investigate the antibacterial effect of arginine (Arg) in NaF toothpaste. 24-h mono-/3-species biofilm cultures of S. mutans, S. sanguis and S. gordonii inoculated sHA discs were subjected to treatment with toothpaste supernatants prepared as - [1]:2% Arg –NaF (0.147% F), [2]:4% Arg–NaF (0.144% F), [3]:8% Arg – NaF (0.138% F), [4]:NaF (0.15%) and [5]:deionized water. After 24-h incubation, the mono-species biofilms were subjected to viability assay using WST-8, SEM and confocal imaging (CLSM). The 3-species biofilm were quantified for bacterial composition by PCR analysis, SEM, CLSM, and RNA isolation with reverse-transcription PCR analysis. Increasing arginine concentrations in NaF toothpaste had no effect on microbial viability. The mono-/3-species biofilm imaging depicted that the 2% Arg-NaF and 4% Arg-NaF had a biofilm disrupting effect. The 3-species biofilm bacterial composition indicated that the 2% Arg-NaF group maintained an ecological homeostasis by inhibiting S. mutans growth and enriching the growth of S. sanguis and S. gordonii. The 2% Arg-NaF group significantly downregulated the expression of virulent gtfB gene and upregulated the expression of sagP with relative dominance of arcA. Incorporation of 2% arginine in NaF toothpaste might enrich the alkali-producing bacteria and provide enhanced counter mechanisms against cariogenic pathogen when compared to NaF toothpaste.

Unerupted permanent incisors and associated dental anomalies

AIM

The aim of the present study was to investigate the association between unerupted permanent incisors and dental anomalies among children and adolescents.

METHODS

The clinical records of patients between January 2005 and December 2014 were retrieved to identify those with unerupted permanent incisors. A retrospective audit on the presence or absence of any dental anomalies was done from all available records of the included patients.

RESULTS

A total of 266 patients with 320 unerupted permanent incisors were identified from the 15 987 patients in the study. Among the unerupted permanent incisors, 222 (69.4%) were associated with dental anomalies, which was significantly higher than those showing an absence of dental anomalies (N = 98, 30.6%, P < 0.001). For the unerupted maxillary central incisors, a significantly higher proportion was associated with supernumerary teeth (P < 0.001). For the unerupted maxillary lateral incisors, a significantly higher proportion was associated with the ectopic eruption of permanent canines when compared with other dental anomalies (P < 0.001). The presence of the ectopic eruption of permanent canine, double teeth, and hyperdontia was significantly higher among male patients with unerupted permanent incisors.

CONCLUSIONS

Unerupted permanent incisors were associated with supernumerary teeth and ectopic eruption of permanent canines. Specifically, a higher proportion of unerupted maxillary central incisors was associated with the presence of supernumerary teeth, whereas a higher percentage of unerupted maxillary lateral incisors was associated with the ectopic eruption of permanent canines.

Knowledge, perceptions, and clinical experiences on molar incisor hypomineralization among dental care providers in Hong Kong

BACKGROUND

Molar incisor hypomineralization (MIH) is an alarming problem with considerable challenges in management. This study aimed to evaluate and compare the knowledge, perceptions, and clinical experiences of molar incisor hypomineralization (MIH) between general dental practitioners (GDPs) and paediatric dentists (PDs) in Hong Kong.

METHODS

A cross-sectional survey of 557 randomly selected GDPs (approximately 25% of all registered dentists) and all registered PDs (n = 31) were invited. They were asked to complete a 4-section questionnaire adapted and modified from a study by Gambetta-Tessini and co-workers on sociodemographic profiles, knowledge, experience, and perceptions regarding MIH. Data were analyzed with chi-square, Fisher's exact, and multiple factor ANCOVA tests.

RESULTS

The overall response rate was 43.37% (255/588). Majority (74.1%) of the respondents encountered MIH in their practices. A significantly higher mean knowledge score (46.33 ± 7.1) was observed among PDs than GDPs (43.09 ± 7.0) (P < 0.01) and among PDs who are 40 years old or younger (P < 0.001). Differences in treatment of MIH were also observed between PDs and GDPs (P < 0.05). Paediatric dentists were more confident in diagnosing and treating MIH (P < 0.001). Most respondents (87.8%) expressed a need for continuing education on MIH.

CONCLUSION

Continuing education on MIH is needed to assure that the highest quality of evidence-based care is given to patients with MIH. Dissemination of latest best evidence on MIH, especially to GDPs, will assure that the condition is accurately diagnosed and well managed.

Prevalence, characteristic features, and complications associated with the occurrence of unerupted permanent incisors

This study examined the prevalence, characteristic features, and complications associated with the occurrence of unerupted permanent incisors among children and adolescents attending a university dental teaching hospital. A retrospective review was performed of the clinical records of children and adolescents who attended the Prince Philip Dental Hospital, Hong Kong between 2005 and 2014. All patients who had at least one unerupted permanent incisor tooth were included. A total of 266 subjects with 320 unerupted permanent incisors were identified. The prevalence of unerupted permanent incisors among children and adolescents was 2.0%. Permanent maxillary central incisors (70.6%) were the most commonly affected teeth. The most common cause for unerupted incisors were dilacerations (n = 83, 36.7%) for maxillary central incisors; developmental dental anomalies (n = 22; 30.6%) together with unfavorable root development (n = 22; 30.6%) for maxillary laterals incisors; and abnormal tooth/tissue ratio (n = 11, 50.0%) for mandibular incisors. A majority of unerupted incisors presented with complications the most common being ectopic/displacement/rotation of the unerupted incisors (46.6%), loss of space (36.9%) and midline shift (27.5%). In conclusion, the causes were distinct for different manifestations of unerupted permanent incisors. As the majority of unerupted incisors presented with complications, a systematic and organized method of history taking as well as clinical and radiographic examinations is mandatory in the diagnosis of unerupted permanent incisors.

Genetic basis of dentigerous cysts associated with supernumerary teeth: A narrative review

In the present study, we sought to: (a) analyze the p53 gene status in dentigerous cysts (DC) associated with supernumerary teeth (ST) in a pair of siblings with ST, of whom one developed a DC; and (b) conduct a narrative review of the literature on ST associated with DC. Blood samples were obtained, and the isolated DNA was used to amplify exons 4-8 of the p53 gene using specific primers, and subsequently sequenced. No mutations were identified in the coding regions of the p53 gene. A review of the literature revealed a prevalence of DC associated with ST to be as high as 13.6%, and that 83% of the case reports performed enucleation of DC and removal of ST. Dentigerous cysts associated with ST in one sibling demonstrated that variations in phenotypes exist, and the absence of mutations cannot eliminate the potential influence of genetic risk factors.

A Review of Enamel Remineralisation Potential of Calcium- and Phosphate-based Remineralisation Systems

PURPOSE

Along with calcium and phosphate ions, fluoride ions promote remineralisation of noncavitated carious lesions to form fluorapatite. However, the supply of calcium and phosphate ions from saliva may not be adequate for effective remineralisation in patients with high caries risk. Therefore, an additional supply of calcium and phosphate ions is mandatory to enhance effective remineralisation with fluoride ions. Several calcium- and phosphate-based remineralisation agents are available for clinical use. However, the nature of the incorporated calcium and phosphate ions and the method of their stabilisation are not similar. Therefore, this review summarises research findings on the enamel remineralisation potential of calcium- and phosphate-based remineralisation agents.

MATERIALS AND METHODS

Appropriate key words were used and the Pubmed electronic database was searched to retrieve articles. Screening through titles and abstracts identified relevant articles. Full text review of the identified relevant articles was performed and the significant findings were summarised and presented in this review.

RESULTS

Several studies including laboratory-based studies, in situ and randomised controlled clinical trials showed casein phosphopeptide amorphous calcium phosphate (CPP-ACP)-containing remineralisation agents to have superior remineralisation potential compared to other forms of calcium- and phosphate-based remineralisation agents, such as functionalised tri-calcium phosphate (fTCP) and amorphous calcium phosphate (ACP).

CONCLUSIONS

More long-term clinical studies are necessary to compare the enamel remineralisation potential of calcium- and phosphate-based agents that contain fTCP and ACP with those containing CPP-ACP. Additional well-designed randomised controlled clinical trials are also necessary to justify long-term clinical supplemental use of products containing CPP-ACP.

Effect of different fluoride varnishes on remineralization of artificial enamel carious lesions

OBJECTIVES

To compare remineralization potential of topical fluoride varnishes with added calcium phosphate-based delivery systems on artificial enamel caries.

METHODS

Human enamel specimens (n = 60) were randomly divided into six groups: Group 0: Control (no varnish), Group 1: Duraphat^® , Group 2: MI Varnish^™ , Group 3: Embrace^™ Varnish, Group 4: Enamel Pro^® Varnish, and Group 5: Clinpro^™ White Varnish. Specimens were immersed in demineralizing solution for 96 h to create artificial caries lesion. Each specimen was then immersed in artificial saliva for 6 h after fluoride varnish application and pH cycling was performed for 8 days. Specimens were evaluated using Knoop surface microhardness (KHN) and transverse microradiography (TMR). One-way anova test was performed to examine the effect of fluoride varnishes on change in percentage of surface hardness recovery (%SHR), change in lesion depth (ΔLD), and change in mineral loss (ΔΔZ) with the significance limit set at 5%.

RESULTS

%SHR of enamel following treatment with Group 1 was significantly higher than Group 3 and Group 4. Conversely, ΔLD and ΔΔZ of Group 1 were significantly higher than Group 2, Group 3, and Group 4. No significant differences in %SHR, ΔLD, and ΔΔZ were found between Group 1 and Group 5.

CONCLUSIONS

Duraphat^® alone achieves significant remineralization of enamel carious lesions. Clinpro^™ White Varnish had similar enamel remineralization effect as Duraphat^® .

Quality of life changes in children following emergency dental extractions under general anaesthesia

OBJECTIVES

To assess the changes in the oral health-related quality of life (OHRQoL) of 221 preschool children who presented to the emergency department with the consequences of untreated dental caries requiring dental extractions under general anaesthesia (DEGA).

METHODS

Two hundred and twenty-one healthy preschool children, who required emergency DEGA, were recruited over a period of 12 months. The same parent or caregiver completed the Early Childhood Oral Health Impact Scale (ECOHIS) questionnaire; both, prior to the DEGA and at the 2-week post-treatment visit. Data were analysed using repeated anova with adjustments for multiple comparisons using the Bonferroni tests with the significance level set at 5%.

RESULTS

One hundred and twenty-six participants, with a mean age of 4.02 and a mean dmft score of 8.27 (SD = 4.13), completed the 2-week post-treatment questionnaires. The overall ECOHIS, CIS, and FIS scores decreased significantly (P < 0.001) after emergency DEGA, demonstrating large effect sizes. The biggest decrease in prevalence after emergency DEGA was observed for the items of pain in teeth, trouble sleeping, being irritated or frustrated, difficulty drinking food, and parents being upset.

CONCLUSIONS

The OHRQoL of preschool children, who presented to the emergency department with the consequences of untreated dental caries, was significantly improved following emergency DEGA.

Changes in the oral health-related quality of life in children following comprehensive oral rehabilitation under general anaesthesia

OBJECTIVES

To assess changes in the oral health-related quality of life (OHRQoL), after comprehensive oral rehabilitation under general anaesthesia (CORGA), among children (i) <6 years using the Early Childhood Oral Health Impact Scale (ECOHIS) and (ii) aged 6-14 years using the child oral health-related quality of life (COHRQoL) instrument.

METHODS

A total of 136 healthy children who had CORGA were recruited over a period of 12 months. The parent or caregiver of the study participants completed the age-appropriate questionnaire prior to the dental treatment and at the subsequent follow-up appointments (2 weeks and 3 months). Data were analysed using repeated-measures anova and Bonferroni tests.

RESULTS

The overall ECOHIS scores decreased significantly (P < 0.001) demonstrating large effect sizes. The greatest decreases were for the domains of child oral symptoms (57.5%) and psychology (38.7%) in the child impact section (CIS) and for the domain of parental distress (38.9%) and family function (40%) in the family impact section (FIS). For COHRQoL, the overall P-CPQ and FIS scores decreased significantly for all items (P < 0.001), demonstrating large effect sizes. The greatest decreases were for the domains of oral symptoms (77.7%), functional limitations (74.3%), and the FIS (80.1%).

CONCLUSIONS

The OHRQoL of children in both age groups (<6 and 6-14 years) was significantly improved after CORGA.

Effect of Solvents on Dentin Collagen Cross-linking Potential of Carbodiimide

PURPOSE

This study compared the dentin collagen cross-linking potential of carbodiimide (EDC) prepared in three most commonly used solvents in dental adhesive systems: water, ethanol, and acetone.

MATERIALS AND METHODS

Thirty-eight extracted caries-free human permanent molars were used in this study. Demineralized dentin beams were prepared and cross linked by 0.3 M EDC in water, acetone, or ethanol. The modulus of elasticity of demineralized dentin, the resistance of dentin matrix to enzymatic degradation, the swelling ratio, and the mass change of demineralized dentin matrix were examined to compare the cross-linking efficacy of EDC in their respective solvents.

RESULTS

The modulus of elasticity of demineralized dentin cross linked by EDC in acetone was significantly higher (p < 0.05) than demineralized dentin cross linked by EDC in ethanol and EDC in water. Furthermore, the ultimate tensile strength of demineralized dentin cross linked by EDC in water and ethanol dropped significantly following enzymatic degradation, while the ultimate tensile strength of demineralized dentin cross linked by EDC in acetone was preserved. The swelling ratio of demineralized dentin cross linked by EDC in acetone and ethanol was significantly lower (p < 0.05) than that of demineralized dentin cross linked by EDC in water. Conversely, the mass change of demineralized dentin cross linked by EDC in acetone was significantly higher (p < 0.05) than demineralized dentin cross linked by EDC in water and EDC in ethanol.

CONCLUSION

The dentin collagen cross-linking potential of EDC could be enhanced by using acetone as a solvent.

Adjunctive application of chlorhexidine and ethanol-wet bonding on durability of bonds to sound and caries-affected dentine

OBJECTIVES

To examine the effect of adjunctive application of chlorhexidine (CHX) and ethanol-wet bonding (EWB) on bond durability and nanoleakage of hydrophobic adhesive to sound (SD) and caries-affected dentine (CAD).

METHODS

Dentine surfaces of molars were etched after caries removal and randomly allocated to four groups (n=12). In Groups 1 and 2, dentine surfaces were saturated with either 2 ml of 100% ethanol or 2 ml of ethanol with 2% CHX for 60s. In Groups 3 and 4, dentine surfaces were saturated with either 15 μL of distilled water or 15 μL of distilled water with 2% CHX for 60s. Two coats of primer, followed by neat resin were applied and light-cured for 40s. Resin composite build-ups were placed and bonded specimens were sectioned for bond strength testing after 24 h and 12 months' storage in artificial saliva. Bond strength data were analyzed using 3-way ANOVA and SNK tests. Interfacial nanoleakage was evaluated after 24 h and 12 months using a field-emission scanning electron microscopy and data were analyzed using Kruskal-Wallis test.

RESULTS

Significant differences were observed for the three factors: "substrate" (p<0.001), "rewetting agents" (p<0.001) and "time" (p<0.001) on bond strength. Incorporation of 2% CHX to EWB preserved bond strength to SD and CAD and reduced interfacial nanoleakage after 12 months. Incorporation of 2% CHX to WWB also preserved bond strength to SD after ageing.

CONCLUSIONS

Incorporation of chlorhexidine to ethanol-wet bonding has an interaction effect on preservation of bond durability to sound and caries-affected dentine.

CLINICAL SIGNIFICANCE

Incorporation of chlorhexidine to ethanol-wet bonding with hydrophobic adhesive enhances the success rate of aesthetic bonded restorations.