Elemental composition, corrosion resistance and mechanical properties of computer-aided design and computer-aided manufacturing fixed retainers versus conventional fixed retainers

PURPOSE

To investigate the elemental composition, corrosion resistance, and mechanical properties of computer-aided design and computer-aided manufacturing (CAD-CAM) retainers versus conventional fixed retainers (FRs).

METHODS

Eight different retainer wires were investigated. Energy dispersive X-ray spectroscopy was used to determine the elemental composition. Leakage was analysed according to ISO 10271:2020 guidelines. Hardness was tested using the Vickers method with a load of 0.3 kg. The tensile force and tensile strength were evaluated. Multiple comparisons among wires of hardness, tensile force, and strength were conducted using the Welch t-test, with Bonferroni correction.

RESULTS

Nickel was present in all wires. The CAD-CAM-FR wire, which contained more nickel than the other wires, had no measurable leakage. The gold-plated wires had the highest total leakage, but did not exceed the ISO standard limit. The hardness of the stainless-steel twisted wires was the highest and that of the CAD-CAM-FR wire was the lowest. The tensile strength of the CAD-CAM-FR wire was significantly lower than that of the other wires and similar to the other twisted-wire retainers.

CONCLUSION

The CAD-CAM-FR wire is likely to have high corrosion resistance and flexibility due to its low hardness.

Deterioration of direct restorative materials under erosive conditions with impact of abrasion and attrition in vitro

Objective

To compare the cumulative impact of sequential wear on mechanical properties and appearance of a composite resin (CR), Filtek Z250^®, a glass ionomer GI, Fuji IX GP^®, and a glass hybrid (GH), Equia Forte^®.

Material and Methods

Six equally sized specimens of each material were subjected to wear tests, i.e., simulation of brushing, chewing and acidic liquid exposure, mimicking at least 6 months of clinical exposure. Surface roughness, hardness, substance loss and degree of shade lightness were determined.

Results

Following wear tests, significant increase in surface roughness and decrease in hardness values were observed for all materials (p < .05). Significantly larger substance loss was found in Equia Forte^® specimens compared to Filtek Z250^® (p < .05), while that of Fuji IX^® exceeded the measurement capacity of the instrument. Opposite to the two other materials, the shade of Filtek Z250^® became darker.

Conclusions

Sequential wear exposure mimicking abrasion, erosion and attrition to products representing CR, GI and GH, caused weakening and change in appearance of the materials. The composite resin was the most mechanically resistant to the sequential wear.

Association of locus Xq26.1 - 27.3 with Erosive Tooth Wear Phenotypes in a Group of Adolescents

Erosive tooth wear is a multifactorial condition of an increasing prevalence. There is a need for discovering individual genetic predisposition for the development of this condition. Considering that the chromosome X locus was shown to be associated with dental caries, the aim of the present study was to look for the association between this locus and erosive tooth wear when dietary habits are considered as a co-factor. Saliva samples, erosive wear experience data, and dietary information from 16-18 year-old dental patients (n=705) were used. Genotyping analyses were performed, and thereafter, analyses considering diet and oral hygiene data, using logistic regression, with the assumption that erosive tooth wear is a complex gene-environment model. Genotypic analyses revealed an association between chromosome X marker rs1324156 and erosive tooth wear phenotype. Logistic regression analysis showed that, in the presence of less common allele of rs12687601 and rs1324156, erosive tooth wear more likely develops when associated with numerous dietary variables from the questionnaire. These results indicate that erosive tooth wear may be the result of gene-environment interactions.

Relationship Between Dental Caries and Erosive Tooth Wear in Adolescents

Background

Our aim was to investigate the relationship between caries experience and erosive tooth wear of adolescents.

Methods

We compared the Decayed, Missing, and Filled Teeth (dmft/DMFT) data of 795 adolescents to their erosive tooth wear scores using diet as a covariate and determined if dental caries and erosive tooth wear scores are associated using linear regression analysis. Diet data and oral hygiene habits were collected using self-reported surveys and erosive tooth wear scores were previously collected. We also compared patients' genotypes and phenotypes and looked for an association between erosive tooth wear experience and different single nucleotide polymorphisms (SNPs). A Bonferroni correction was implemented to correct multiple comparisons. Two-group comparisons were made depending on the phenotype definitions implemented, and both chi-square and linear regression analyses were used to test association between genetic variants and caries definitions. All covariates were included in each model.

Results

For four SNPs (rs17159702, rs10246939, rs1800972, and rs1676303), there was an association between a spike in caries experience of DMFT 4 or more between two time points and increased frequency of fruit juice intake. A fifth SNP rs2860216 was shown to be a protective factor toward a spike in caries when coupled with more frequently eating yogurt. We did not find significant associations between our dental caries phenotypes or our demographic data and erosive tooth wear status in our linear regression.

Conclusions

Dental caries and erosive tooth wear are two diseases that differ in mechanism and heritability.

Survival of primary molars with pulpotomy interventions: public oral health practice-based study in Helsinki

OBJECTIVES

To assess long-term survival of pulpotomized primary molars and factors related to the survival of the teeth.

MATERIALS AND METHODS

This retrospective longitudinal study was based on electronic dental health records of children who attended public health service. Eligible children were <12 years and had a pulpotomy procedure code in their dental treatment history. Data were obtained in the period between 2002 and 2016. Chi-squared test, t-test, and one-way ANOVA were used to assess for statistical differences. Kaplan-Meier analyses were performed to create survival estimates, and the log-rank test was performed to compare differences in survival distributions. A multivariate Cox regression was conducted, and hazard ratios were calculated to estimate the hazard rate for failure.

RESULTS

Of interventions, 40% were registered in children 3-6 years of age; 56% were boys. Mean estimated survival of such molars was 82 months (SEM = 0.6) and differed by dental operator's work setting and choice of restorative materials used after pulpotomy intervention. Using a stainless steel crown (SSC) to restore pulp-intervened primary molars had the strongest effect on survival (111 months with SEM = 1.8), followed by if the intervention was performed by a specialist or specializing dentist in paediatric dentistry (99 months with SEM = 2.6).

CONCLUSIONS

The estimated survival time of pulpotomized primary molars is affected by dental operator-related factors, which should be considered in management of extensively carious primary molars of paediatric patients, both at the clinical and organizational decision-making levels. An increased focus on the use of SSC is recommended to be in the learning objectives of dental education programs.

Knowledge on and treatment practices of erosive tooth wear among Finnish dentists

OBJECTIVES

To investigate Finnish dentists' knowledge on and means of recording, detecting and diagnosing erosive tooth wear (ETW). Treatment options and possible differences in treatment decisions between general and specialized dentists were also evaluated.

MATERIALS AND METHODS

An electronic questionnaire was sent by e-mail to 3664 Finnish dentists. Respondents' gender, age, work experience, field of specialty, and practice location were requested. The questionnaire also included a patient case where the dentists were asked about their choice of treatment. Statistical analyses were performed using means, proportions, and cross tabulations.

RESULTS

Response rate was 24% (n = 866). Almost all respondents (98.0%) recorded ETW in patient files, but only 4.1% used a detailed scoring system. Of the respondents, 64.4% usually found the cause of ETW. Use of carbonated beverages (84.3%), energy drinks (57.0%), and reflux disease (53.1%) were reported to be probable causes. The majority of the respondents (80.9%) usually assessed patient's dietary history while 1.9% evaluated saliva secretion rate. When asked about treatment decisions of ETW patients, the differences between general dentists and specialized dentists were not as obvious as hypothesized.

CONCLUSIONS

This study suggests that the Finnish dentists who participated in this survey are able to detect and/or diagnose erosive tooth wear, but there is variation in recording it. The differences in treatment decisions between general dentists and specialized dentists seem to be moderate. The treatment practices for ETW are not established and further research to create clinical guidelines seems to be needed.

Stainless-steel crowns in children: Norwegian and Finnish dentists' knowledge, practice and challenges

BACKGROUND

Stainless-steel crowns (SSCs) are recommended for restorative treatment of young teeth severely affected by caries, fractures or dental developmental disorders (DDDs). However, despite recommendations and clinical evidence, SSCs are not widely used by general dentists, who favour extraction and more conventional restorations. The present study aimed to investigate the views of and use of SSCs among Norwegian and Finnish dentists.

METHODS

The present study was a cross-sectional survey among Norwegian and Finnish dentists. An electronic questionnaire was sent to Norwegian and Finnish dentists asking whether they used SSCs and on which indications. In addition, the questionnaire assessed reasons for non-use and dentists' perceptions regarding advantages and challenges in the use of SSCs, as well as the need for additional training. Distributions of background characteristics, use of and views on SSCs were calculated, and statistical significance of the associations between respondents' background and their answers were evaluated.

RESULTS

Of the 574 Norwegian and 765 Finnish respondents, only 12.0% and 12.9% reported to use SSCs, respectively. The most frequently reported barrier reported by those who did not use SSCs was lack of practical training. The most frequent challenge reported by those using SSCs was difficulties in crown adjustment followed by aesthetic issues, and the most frequently reported advantage was that SSCs maintain the function and occlusion. The majority of respondents reported a need for more information and practical training in the use of SSCs, with hands-on course as their most frequently preferred education type.

CONCLUSION

Although the value of SSCs for restoring young molars is recognized by Norwegian and Finnish dentists, SSCs are rarely used by general dentists. The majority of the respondents reported lack of training and materials and was interested in receiving more information and education.

In vitro abrasivity and chemical properties of charcoal-containing dentifrices

Objective

Charcoal-containing dentifrices are gaining popularity, but scientific information on their effect on oral health is scarce. This study investigated properties of dentifrices that may affect dentine abrasivity, as well as their ability to adsorb fluoride, their pH and the presence of harmful substances.

Materials and methods

The dentifrices NAO and COCO were subjected to the following analyses: abrasivity, expressed as mean abraded depth and relative dentin abrasivity (RDA), and surface roughness of extracted human molars (n = 30) after simulated brushing; fluoride adsorption measured as concentration change; pH measurements; detection of polycyclic aromatic hydrocarbons by gas chromatography–mass spectrometry. The products were compared to a reference dentifrice (Colgate^® MaxWhite), positive controls (ISO dentifrice slurry, activated charcoal for laboratory use) and a negative control (distilled water).

Results

The mean abraded depths of NAO and COCO were not different (p > .05), but higher than the reference dentifrice and the negative control (p < .05). The RDA values of NAO, COCO and the ISO dentifrice slurry were higher than the reference dentifrice value (p < .05) by up to 10 times. The dentine surface roughness was higher after brushing with NAO, COCO and ISO dentifrice slurry compared to distilled water (p < .05). No change in mean adsorbed fluoride concentration was observed after 24 h (p > .05). Both NAO and COCO were alkaline (pH > 7). Analysis of NAO revealed the presence of naphthalene (112.8 ± 2.0 ng/mL).

Conclusion

The charcoal-containing dentifrices were abrasive within acceptable limits set by ISO and did not adsorb fluoride. The presence of naphthalene in one product is a cause for concern.

Awareness, knowledge and treatment decisions for erosive tooth wear: A case-based questionnaire among Danish dentists

Objective

To examine the knowledge and experience of erosive tooth wear (ETW) among Danish dental practitioners and, based on two cases, explore their treatment decisions.

Methods

We sent a validated questionnaire electronically to all active members of The Danish Dental Association and The Association of Public Health Dentists in Denmark. The questionnaire had two parts; the first focused on scoring, recordkeeping, knowledge and experience of ETW. The second part presented two patients with different severity of erosive lesions to explore the dentists preventive and restorative treatment decisions.

Results

We received 442 answers from 4,490 potentially eligible dentists in Denmark (response rate 9.8%). The majority (78%) was female and the median age was 44 years. Nearly all respondents (97%) registered ETW in the charts and 49% recorded “always” or “often” the patients' diet history, most commonly with aid of interviews. The respondents perceived the prevalence of ETW to be higher today than 10–15 years ago and male patients (15–25 years) appeared more affected than females. The majority (82%) thought that they usually found the probable cause of the condition with carbonated beverages being the most common factor. The treatment included dietary guidance, soft tooth brushing with non‐abrasive fluoride toothpaste, topical fluoride applications and direct composite restorations.

Conclusion

The majority of Danish dentists taking part of this survey had adopted a minimally invasive approach for the management of erosive tooth wear in young adults. There was however room for improvements in diagnosis, scoring and case documentation.

Estimating molar-incisor-hypomineralization among 8-year-olds based on 15-year public oral health practice-based data

Background: A wide range in the prevalence of molar-incisor-hypomineralization (MIH) has been reported. Population-based studies are recommended. However, such studies are expensive and time-consuming.Objectives: To estimate the magnitude of MIH condition among 8-year-olds based on routine oral health examinations and to associate first permanent molar (FPM) affection with that of other permanent teeth over time.Materials and methods: This retrospective study, with cross-sectional and longitudinal components, was based on electronic oral health records; all 8-year-olds examined between 2002 and 2016 were included.Results: The average estimated prevalence of MIH was 8.3%; yearly range was 4.8-15.9%. The mean number of affected teeth was 1.4; 62% had one affected tooth. One-surface defects were the most frequent (66%). Asymmetric distribution of affected teeth was observed. In follow-up, 10.7%, 8.4%, and 11.2% had at least one affected permanent canine, premolar, or second permanent molar, respectively. The proportion of children with other MIH-affected permanent teeth was higher in the group with ≥2 MIH-affected teeth than in group with one affected FPM at the age of 8.Conclusions: The average prevalence of MIH was comparable to that reported elsewhere. The number of MIH-affected teeth at early mixed dentition predicts the affection of other permanent teeth over time, mainly that of permanent canines. Further screening of children with MIH is recommended to improve individually tailored early preventive and restorative dental care.

Functional, compositional, and regulatory analyses of imported and non-imported single dental crowns

The aims of the study were to investigate functional and esthetic properties, the composition of the alloy, and the content of hazardous elements of single dental crowns with metal skeleton and fired porcelain. Epoxy models made from full mouth impressions taken of a patient with a crown preparation of the right maxillary first permanent molar were used for production of identical polyether impressions, which were distributed to dentists in Norway. The dentists sent the impressions to their regular dental laboratories. All 55 crowns collected were anonymized and examined. Of the crowns received, 35 were made in Norway, 12 were imported, and 8 were of unknown origin. The evaluation of functional properties revealed that 50% of the Norwegian, 42% of the imported, and 25% of the unknown-origin crowns were considered unacceptable. The composition of the alloy was not in accordance with that stated by the manufacturer for 17%, 13% and 20% of the crowns, where this information was provided. The lead content of the alloy exceeded the limit set by the ISO 22674: 2016 for 18% of the crowns in total. The statement that shall follow the work according to EU-regulations was not complete for approximately 75% of the works received.

Dental erosion in mice with impaired salivary gland function

Objective: Salivary flow rate exerts an essential impact on the development and progression of dental erosion. In this work, the experimental dental erosion in non-obese diabetic (NOD) mice with reduced salivary flow rate was induced, and the erosive effect of acidic drinks on their dentition was studied.Material and methods: Three acidic drinks (sports drink, cola light drink and sugar containing cola drink) were given to adult NOD mice (groups: N = 11) as the only drink for 6 weeks. Two control groups were included; wild type and NOD control (groups: N = 9). Experimental and control (water) teeth were dissected out and observed by scanning electron microscopy (SEM). Mandibular first molars were subsequently embedded in Epon, ground transversely, observed again by SEM, and the enamel thickness and tooth height were measured.Results: Mandibular molars were considerably more eroded than maxillary molars. The erosive process started at the top of the cusps and subsequently extended in the cervical, mesio-distal, and pulpal direction. Erosive lesions were evident in increased succession from sports drink, cola light to cola drink exposed mandibular molars, with the lingual tooth height being approximately 23%, 26%, and 37% lower, respectively, compared to the control. The lingual enamel was approximately 48% thinner in sports drink molars and 62% thinner in cola light molars. In cola drink molars, the lingual enamel was totally eroded, and significant erosion of dentine was evident.Conclusion: Reduced salivary flow, together with a high consumption of acidic drinks, results in severe erosion of NOD mice molars.

Restorative material choices for extensive carious lesions and hypomineralisation defects in children: a questionnaire survey among Finnish dentists

AIM

This survey assessed Finnish dentists' treatment decisions and choices of restorative materials in selected paediatric dental patient cases, with special emphasis on stainless steel crowns (SSCs).

METHODS

A questionnaire with patient descriptions and tooth photographs was e-mailed to members of Finnish Dental Society (n=3,747). The respondents were asked to choose their preferred treatment in cases describing 1) extensive occlusal carious lesion in a primary molar of a cooperative child; 2) an identical lesion, treated under dental general anaesthesia (DGA); and 3) a symptomatic first permanent molar with enamel hypomineralisation (consistent with Molar-Incisor Hypomineralization, MIH) and post-eruptive breakdown. Only responses from dentist treating children were included (final n=765).

RESULTS

The majority (47.3%) would have preferred restoration of the extensive primary tooth caries in a normal setting using resin-modified glassionomer cement, and 4.3% by using SSC. The preference of SSC as treatment choice increased to 25.4% upon implementation of DGA. The majority would treat the symptomatic permanent MIH molar with a resin composite restoration (45.0%), while 10.5% suggested SSC. Compared to general dentists, paediatric dentists had a stronger preference for SSCs.

CONCLUSIONS

Although the respondents emphasised patient cooperation, but also tooth prognosis and material strength behind their treatment decisions, SSC was an uncommon choice.

Aquaporins' Influence on Different Dental Erosive Wear Phenotypes in Humans

Dental erosive wear is a multifactorial condition of high prevalence. Nowadays, there is an emphasis on discovering individual genetic predisposition for the development of this condition. Aquaporins (AQPs) are water channel proteins expressed in salivary glands, as well as during tooth development. They are involved in salivary secretion and composition and linked to physiological protection of the oral cavity. The aim of this study was to explore the relationship between different dental erosive wear phenotypes, AQP genes, and selected environmental factors. Data from 705 dental patients were used to investigate the association between dental erosive wear phenotypes and AQPs' single-nucleotide variants. Phenotypes were further analyzed considering diet and oral hygiene data, using logistic regression analysis, as implemented in PLINK, with the assumption that dental erosive wear is a complex gene-environment model. Associations were found between severe erosive tooth wear and rs2878771 (AQP2) for the genotypic (p = 0.02) and dominant (p = 0.03) models, and rs3736309 (AQP5) for the allelic model (p = 0.02). Logistic regression analyses, after implementing the Bonferroni correction, showed that several significant associations were present when covariates were included, suggesting that a strong environmental component is present. Our results show that dental erosive wear establishes under a gene-environmental complex model.

The frequency of enamel and dentin caries lesions among elderly Norwegians

Aim: To describe the distribution of enamel-, dentin-, root- and secondary caries within an elderly population in Northern-Norway.Material and methods: A study population (n = 1 173) was divided into age groups: 65-69 (seniors), 70-74 (young elderly), 75-79 (elderly) and 80-94 (old elderly). Seven examiners registered presence, location and severity of caries lesions on x-rays and intra-oral photos. Severity of approximal, occlusal, secondary and root caries was graded (D_1-2: into enamel; D_3-5: into dentin, root caries)_, and decayed missing filled surfaces/teeth (DMFS/DMFT) were calculated. T-test, ANOVA and a Bonferroni correction were used.Results: The seniors had more primary caries (DS_1-5) compared to the oldest age groups, while the old elderly had significantly more secondary caries than the other groups (p < .05). Of those ≥65 years 13.8% were affected with root caries, 21% among the oldest. About 48% of the old elderly had one or more surfaces with untreated caries lesions into dentin, while for the other groups the number was 35% (p < 0.05).Conclusion: Individuals seem to maintain good oral health up to at least 80 years of age. Those older than 80 years have more root caries needing more intensified caries-controlling measures and a higher prevalence of untreated dentin lesions often in need of operative treatment.

How serious is Molar Incisor Hypomineralisation (MIH) among 8- and 9-year-old children in Bosnia-Herzegovina? A clinical study

AIM

To determine the prevalence of MIH in 8- and 9 year-old children in the city of Kljuc, Bosnia-Herzegovina, and to describe the distribution and severity of the affected teeth.

MATERIALS AND METHODS

Study design: All 8- and 9-year-olds (n=104) living in Kljuc (born 2004/2005) were invited to participate, and 103 were examined by a calibrated clinician. Written, informed consent was obtained from all participants' relatives, as well as a questionnaire designed to assess potential risk indicators. Index teeth were all permanent first molars and incisors (12 teeth). Opacities (>1mm), post eruptive breakdown (PEB), atypical restorations and previous extractions caused by MIH were registered.

RESULTS

The prevalence of MIH was 11.7% (n=12), significantly higher for girls than for boys (14.6% vs. 9.7%; p<0.05). The maxillary first molars and incisors were 1.8 (p<0.02) and 2.3 (p<0.05) times more frequently affected than the mandibular ones, respectively. Seven (30%) of the affected molars had opacities, 8 (35%) had PEB and 8 (35%) atypical restorations. No molars had been extracted due to MIH. The use of penicillin due to adenoid infections in the first 5 years was associated with a higher prevalence of MIH (41.7% vs. 19.6%).

CONCLUSIONS

The prevalence of MIH (11.7%) supports the data previously published from Bosnia-Herzegovina. Girls had higher prevalence of MIH than boys; first molars and incisors in the maxilla were almost twice as often affected as in the mandible. Use of penicillin in the first 5 years was associated with a higher prevalence.

Treatment decisions regarding caries and dental developmental defects in children - a questionnaire-based study among Norwegian dentists

BACKGROUND

Current knowledge on treatment strategies and choice of restorative materials when treating deep caries or severe dental developmental defects (DDDs) in young individuals is scarce. Therefore, the aim was to investigate Norwegian dentists´ treatment decisions and reasons for treatment choice when treating deep caries in primary teeth and severe DDDs in permanent teeth in children.

METHODS

A pre-coded questionnaire was sent electronically to all dentists employed in the Public Dental Service (PDS) in Norway (n = 1294). The clinicians were asked about their background characteristics and how often they registered DDDs. Three clinical cases were presented to the dentists and asked to prioritize treatment options and reasons for their choice.

RESULTS

After three reminders, 45.8% of the dentists answered. Most clinicians were general practitioners (96.3%), females (77.9%), under 41 year-olds (59.4%), graduated in 2001 or later (61.1%), and representing all regions of Norway. The respondents registered molar incisor hypomineralisation (MIH), other DDDs and dental fluorosis (DF) frequently, 523 (91.1%), 257 (44.8%) and 158 (27.5%), respectively. In case 1a with severe dental caries in a primary molar, the preferred treatment was resin-modified glass ionomer cement (RMGIC) (58.3%), followed by glass ionomer cement (GIC) (17.9%) and zinc oxide-eugenol (ZOE) (13.2%). Extraction, compomer or stainless steel crowns (SSC) were preferred by 0.9, 0.7 and 0.4%, respectively. In case 1b, which was identical to case 1a, but treated under general anaesthesia, the preferred treatment alternatives were RMGIC (37.1%), resin composite (RC) (17.6%) and GIC (17.2%). Extraction and SSC were chosen by 15.1 and 7.2%, respectively. In case 2, showing a severely hypomineralised and symptomatic first permanent molar, the dentists preferred RC (38.4%), followed by RMGIC (26.6%) and GIC (19.0%). Extraction and SSC were chosen by 8.7 and 5.4%, respectively. The treatment choices were not significantly affected by the dentists' background characteristics. The reasons for dentists' treatment decisions varied for each patient case; patient cooperation, prognosis of the tooth and own experience were the dominant reasons.

CONCLUSIONS

A notable disparity in treatment choices was shown indicating that Norwegian dentists evaluate each case individually and base their decisions on what they consider best for the individual patient.

New animal model of extrinsic dental erosion-Erosive effect on the mouse molar teeth

OBJECTIVE

Consumption of acidic food and drinks is considered as important risk factor for development of dental erosion. There are several in vitro and in situ studies focusing on the risk indicators and preventive treatment, however, the need for a standardized animal model has been emphasised for many years. The aim was to establish an animal model of extrinsic dental erosion, which may serve as a standard for future studies to improve our understanding of the erosion.

DESIGN

Two acidic drinks, sports drink and cola drink, were given to young mice for six weeks. Experimental and control (water) molars and incisors were dissected out and observed by scanning electron microscopy (SEM). Mandibular first molars were subsequently ground transversely and observed again by SEM. The tooth height and enamel thickness were measured on the SEM images.

RESULTS

The lingual surface of the mandibular molars was most eroded after consumption of acidic drinks. The cola drink exhibited higher erosive effect on mandibular molars compared to sports drink. The lingual tooth height, compared to control, was about 34% and 18% lower in the cola drink and sports drink molars, respectively. Compared to the control molars, the lingual enamel was about 23% thinner in the sports drink molars and totally eroded on the certain lingual areas of the cola drink molars.

CONCLUSIONS

This new animal model of extrinsic dental erosion and the presented method with ground molars observed in SEM are suitable for further studies, which will gain deeper insights into the erosive disease.

Survival of extensive restorations in primary molars: 15-year practice-based study

BACKGROUND

Caries decline in the western world is accompanied by strong polarization among children; 8% of Finnish 5-year-olds having 76% of untreated caries. This high caries risk group needs preventive and restorative strategies.

AIM

To explore survival of extensive restorations in primary molars.

DESIGN

This study was based on health records from 2002 to 2016 of children under 18 years.

RESULTS

Of severely affected primary molars (n = 1061), 41% were restored with preformed metal crowns (PMCs), 38% with glass-ionomer cement (GIC)/polyacid-modified resin composite (PAMRC)/resin-modified GIC (RMGIC), and 21% with resin composites (RC). Younger children (3-8) received 97% of the PMCs and 86% of GIC/PAMRC/RMGIC; older ones (≥9) 91% of the RC restorations. Neither amalgam nor indirect restorations were registered. General dentists (GDs) engaged in primary care restored with GIC/PAMRC/RMGIC (52%) or RC (48%). GDs in general anesthesia care service placed 66% and specializing/specialized dentists 31% of PMCs. PMCs had lower failure rate (1.4% vs 3.0%) than GIC/PAMRC/RMGIC (P = 0.001). Choosing PMCs reduced patient visits compared to other restorations (P < 0.001).

CONCLUSIONS

Severely affected primary molars of children at high caries risk are better managed, using PMCs to optimize the resources in public oral health services.

Redefining the Phenotype of Dental Caries

Dental caries is a multifactorial infectious disease and a major public health problem estimated to affect 60-90% of school children as well as a vast number of adults. The aim of this work was to define patterns of progression of the disease based on longitudinal data in contrast to using a cross-sectional assessment. dmft/DMFT scores were collected at ages 5, 12, 14, 16, 17, and 18 from 876 individuals. We tested our newly defined phenotypes for association with genetic variants in genes shown to be associated with caries. We generated genotyping data using Taqman chemistry in markers of genes involved in processes such as enamel formation and salivary contributions. Kallikrein 4 (KLK4) was found to show a significant association with the created phenotypes (p = 0.0008 in a recessive model for low caries experience in the primary dentition vs. high caries experience in the primary dentition, and p = 0.0004 in a recessive model for caries free primary dentition vs. high caries experience in the primary dentition).

Genetic variation may explain why females are less susceptible to dental erosion

Not all individuals at risk for dental erosion (DE) display erosive lesions. The prevalence of DE is higher among male subjects. The occurrence of DE may depend on more than just acidic challenge, with genetics possibly playing a role. The aim of this study was to investigate the association of enamel-formation genes with DE. One premolar and a saliva sample were collected from 90 individuals. Prepared teeth were immersed in 0.01 M HCl (pH 2.2), and enamel loss (μm) was measured using white light interferometry. DNA was extracted from saliva, and 15 single-nucleotide polymorphisms were analysed. Allele and genotype frequencies were related to the enamel loss of the specimens. Single-marker and haplotype analyses were performed using sex as a covariate. Mean enamel loss was higher for male donors than for female donors (P = 0.047). Significant associations were found between enamel loss and amelogenin, X-linked (AMELX), tuftelin 1 (TUFT1), and tuftelin-interacting protein 11 (TFIP11). Analyses showed significant associations between variation in enamel-formation genes and a lower susceptibility to DE in female subjects. The results indicate that susceptibility to DE is influenced by genetic variation, and may, in part, explain why some individuals are more susceptible than others to DE, including differences between female subjects and male subjects.

Dental erosion: Prevalence and severity among 16-year-old adolescents in Troms, Norway

AIM

To study the prevalence, distribution and severity of dental erosion among 16-year-old adolescents in the Troms region of Norway.

MATERIALS AND METHODS

Study design: The participants were recruited through the Tromsø-study ("Fit Futures"), and 392 16-year-olds were examined for dental erosion using clinical intraoral photographs. Three calibrated clinicians used the Visual Erosion Dental Examination (VEDE) system to register and grade the dental erosive wear.

RESULTS

More than one third (38%) of the participants showed dental erosion on at least one tooth surface, 18% were limited to the enamel, while 20% of the adolescents showed erosive wear extending into the dentine. The occlusal surfaces of the lower first molars, and the palatal surfaces of the maxillary incisors were the most often and most severely affected. Of the participants showing dental erosion, 93% exhibited "cuppings" on the molars, with 48% limited to the enamel and 52% extending into the dentine. The highest prevalence of "cuppings" (73%) was found on the first lower molars, especially the mesiobuccal cusp of the teeth. The prevalence and severity of dental erosion was found to be higher in male than in female participants (p < 0.0001).

CONCLUSION

The results from this study indicate a high prevalence and severity of dental erosion among adolescents in Troms and stress the importance of information, early and effective diagnostics and implementation of prevention strategies.

The Susceptibility to Dental Erosion Differs among Individuals

Studies of wine tasters and patients with self-induced vomiting have revealed that 30-50% of individuals at high risk do not develop erosive lesions. The aim was to investigate this apparent individual susceptibility to enamel erosion. Two enamel specimens were made from each of 3 premolars from 8 persons (donors). Six acrylic mouth appliances were worn by 6 volunteers (carriers). One specimen from each donor was mounted on each appliance. The carriers wore the appliances for 9 days. The appliances were immersed in 0.01 M HCl for 3 min twice per day to imitate a vomiting/reflux situation. The enamel specimens were analysed by a white-light interferometer to measure enamel loss (in micrometres). The enamel loss varied significantly both between the donor teeth (p = 0.009) and the carriers (p = 0.004). The lesion in the specimen with the largest amount of enamel loss was 4 times as deep as in the specimen with the lowest. In 1 carrier, all specimens displayed enamel loss above the mean, including the specimen from the donor with the most resistant enamel. The variation in susceptibility to erosion among individuals appears to be influenced both by the sustainability of the enamel and by factors in the oral environment. This could explain the variation in prevalence and severity of dental erosions among patients exposed to similar acidic challenges. The results suggest that for certain individuals, only minimal acidic challenges may be sufficient to cause damage to the teeth, while others may never develop dental erosions despite extensive exposure to acid.

Enamel formation genes associated with dental erosive wear

Dental erosive wear is a multifactorial condition that is greatly affected by environmental factors. So far, no study has investigated how dental erosive wear is influenced by variations in enamel formation genes. The aim of the present study was to investigate polymorphisms in genes involved in enamel formation and their influence on enamel susceptibility to dental erosion. DNA samples were collected from 795 Norwegian adolescents aged 16-18 years. Five single-nucleotide polymorphism markers were genotyped in selected candidate genes (ameloblastin, amelogenin, enamelin, tuftelin 1 and tuftelin interacting protein 11), reported to influence enamel formation. Allele and genotype frequencies were compared within two patient groups with dental erosions; all participants with dental erosion and only those with severe dental erosion (erosion extending into dentine). Overrepresentation of the G allele of the enamelin marker was seen in the erosion group compared to the unaffected group (p = 0.047). When erosion severity was considered, statistical significant difference in allele frequency was observed for amelogenin, with the C allele suggesting a protective role (p = 0.02). A suggestive overrepresentation of the TT genotype of the amelogenin marker was also seen in cases with severe erosion (p = 0.049) when compared to cases with no dentine erosion. Amelogenin was also associated with severe erosion in the recessive model; the TT genotype was significantly more frequent in the affected group than in the unaffected group (p = 0.01). The present study suggests that polymorphisms in enamel formation genes are statistically associated with an individual's susceptibility to dental erosive wear.

Sour sweets and acidic beverage consumption are risk indicators for dental erosion

This study aimed to investigate the association between dental erosive wear and potential background, behavioural and dietary risk indicators and to assess whether there is a dose-response relationship between the level of acidic beverage consumption and dental erosive wear among adolescents. Of 846 adolescents (aged 16-18 years) scheduled for dental recall examinations, 795 (94%) accepted to participate. All participants completed a self-administered questionnaire regarding their background (gender and age), tooth-brushing frequency and dietary habits (the amount and frequency of acidic food and beverage consumption as well as the chosen method and manner of consuming acidic drinks). The association between the presence of erosive lesions and the possible risk indicators was assessed by logistic regression analyses. Of all participants examined, 37% had ≥3 surfaces with dental erosions and were considered to be affected individuals. In the present study, multivariate logistic analyses revealed a significant association between the dental erosive wear and high consumption of sour sweets and sports drinks. The tooth-brushing frequency was not significantly associated with dental erosive wear. Additionally, to the best of our knowledge, the results are the first to indicate a dose-response relationship between the daily consumption of acidic drinks and dental erosive wear.

May caries-preventive fluoride regimes have an effect on dental erosive wear? An in situ study

OBJECTIVE

High and low concentration NaF regimes have shown caries protective properties, but the preventive effect against erosive/abrasive wear is unclear. AIM. To measure the inhibiting effect on enamel wear of low and highly concentrated sodium fluoride (NaF) toothpastes and a stannous (SnF2) fluoride gel in a single-blind, randomized in situ study, using a White Light Interferometer.

MATERIALS AND METHODS

Sixteen human molars were each divided into four specimens, mounted on acrylic mouth appliances and worn by eight volunteers for 9 days. Experimental procedures were performed in the laboratory. The enamel specimens were brushed every day with fluoride-free toothpaste. Treatments; group 1: no fluoride treatment (control), group 2: SnF2 gel 2500 ppm F (5 min) every third day, group 3: NaF toothpaste 5000 ppm F 5 min every third day and 2 min the other days, group 4: NaF toothpaste 1450 ppm F (2 min) every day. In order to mimic gastric reflux/vomiting, the specimens were etched with 0.01 M HCl for 2 min twice a day.

RESULTS

The mean step height (µm) for the control specimens was -32.9 (SD = 6.8). The mean values for the other groups were -22.2 (SD = 8.4) (group 2), -30.8 (SD = 7.8) (group 3) and -31.4 (SD = 7.7) (group 4). Compared with the control, the SnF2 treated specimens showed significantly lower wear. The NaF toothpastes gave no significant protective effect.

CONCLUSIONS

Application of SnF2 gel every third day gave protection against erosive-abrasive challenges. Daily application of both low concentration and high concentration NaF toothpaste provided no protection.

Dental erosion: a widespread condition nowadays? A cross-sectional study among a group of adolescents in Norway

OBJECTIVE

This study aimed to investigate the prevalence, distribution and severity of erosive wear in a group of 16-18-year-olds in the western part of Norway. A second aim was to describe possible associations between caries experience, socioeconomic background and origin of birth.

MATERIALS AND METHODS

Adolescents (n = 795) attending recall examinations at Public Dental Service (PDS) clinics were also examined for dental erosive wear on index surfaces, using the Visual Erosion Dental Examination scoring system (VEDE).

RESULTS

In total, 795 individuals were examined. Dental erosive wear was diagnosed in 59% of the population (44% erosive wear in enamel only, 14% combination of enamel and dentine lesions, 1% erosive wear in dentine only). The palatal surfaces of upper central incisors and occlusal surfaces of first lower molars were affected the most (33% and 48% of all surfaces, respectively). Cuppings on molars were registered in 66% of the individuals with erosive wear. Erosive wear was significantly more prevalent among men (63%) than women (55%) (p = 0.018).

CONCLUSIONS

There were no significant associations between dental erosive wear and caries experience, socioeconomic background or origin of birth.

Self-induced vomiting and dental erosion--a clinical study

Background

In individuals suffering from eating disorders (ED) characterized by vomiting (e.g. bulimia nervosa), the gastric juice regularly reaches the oral cavity, causing a possible risk of dental erosion. This study aimed to assess the occurrence, distribution and severity of dental erosions in a group of Norwegian patients experiencing self-induced vomiting (SIV).

Methods

The individuals included in the study were all undergoing treatment at clinics for eating disorders and were referred to a university dental clinic for examinations. One calibrated clinician registered erosions using the Visual Erosion Dental Examination (VEDE) system.

Results

Of 72 referred patients, 66 (63 females and three males, mean age 27.7 years) were or had been experiencing SIV (mean duration 10.6 years; range: 3 – 32 years), and were therefore included in the study. Dental erosions were found in 46 individuals (69.7%), 19 had enamel lesions only, while 27 had both enamel and dentine lesions. Ten or more teeth were affected in 26.1% of those with erosions, and 9% had ≥10 teeth with dentine lesions. Of the erosions, 41.6% were found on palatal/lingual surfaces, 36.6% on occlusal surfaces and 21.8% on buccal surfaces. Dentine lesions were most often found on lower first molars, while upper central incisors showed enamel lesions most frequently. The majority of the erosive lesions (48.6%) were found in those with the longest illness period, and 71.7% of the lesions extending into dentine were also found in this group. However, despite suffering from SIV for up to 32 years, 30.3% of the individuals showed no lesions.

Conclusions

Dental erosion commonly affects individuals with ED experiencing SIV, and is more often found on the palatal/lingual surfaces than on the buccal in these individuals, confirming a common clinical assumption.

Awareness and attitudes related to dental erosive wear among 18-yr-old adolescents in Oslo, Norway

The aim of the present study was to describe awareness and attitudes related to dental erosive wear among 18-yr-old adolescents in Oslo and to explore attitudinal differences between participants with and without the condition. All 18-yr-old subjects scheduled for their routine examination at the Public Dental Service clinics during 2008 (n = 3,206) were invited, and 1,456 agreed to participate (a response rate of 45%). The data were collected using structured questionnaires and by clinical examination of the participants. Dental erosive wear was assessed using a pictorial manual - the Visual Erosion Dental Examination scoring system - as a guide. Overall, 88% of participants had heard about dental erosive wear; however, of participants with erosive lesions only 56% were aware of, and only 47% could recall their dentist mentioning, the condition. Participants with erosive wear were more likely to have low or moderate positive attitudes towards acidic drink consumption and to be reluctant to change. In multivariate analyses controlling for gender and behavioural variables, weak or moderate positive awareness of acidic drinks remained significantly associated with higher erosion risk. This study emphasizes the importance of assessment and understanding of awareness and attitudinal aspects in relation to dental erosive wear.

Prevalence and severity of dental erosive wear among a group of Norwegian 18-year-olds

OBJECTIVE

The aim was to study prevalence, distribution and severity of erosive wear in a group of 18-year-olds.

MATERIALS AND METHODS

A total of 1456 adolescents were screened for erosive wear as part of their regular visit at the Public Dental Health Service (PDHS) clinics in Oslo. Of 554 (38%) registered with erosive wear, 267 accepted a second examination to record lesion distribution and severity, performed by one previously calibrated clinician. A tested erosive wear system (VEDE) was used. Occlusal surfaces of the first and second molars in both jaws and the labial and palatal surfaces of the upper incisors and canines were selected as index surfaces.

RESULTS

Of the 267 individuals with erosive wear, 13.5% were without lesions, 54.3% had erosive wear in enamel only, whereas 32.2% had at least one lesion extending into dentine. The upper central incisors (46%) and first lower molars (44%) were the most affected teeth with the highest presence on the palatal surfaces. Cuppings were registered in 62% of the individuals, usually in addition to erosive lesions on other surfaces. Eighty-five per cent of the cuppings were on first molars and 34% on the mesio-buccal cusp. Males had significantly more lesions into dentine compared with females (p = 0.03). There was a significant association between presence of erosive lesions and DMFT (p < 0.01), but no association between lesions and socio-economic or national background.

CONCLUSIONS

A high proportion of adolescents had erosive wear. Cuppings were a common finding.

Registration of dental erosive wear on study models and intra-oral photographs

BACKGROUND

Clinical photographs and study models may provide permanent records of dental erosion and be useful supplements to clinical registration.

AIM

To assess the reliability and validity of registrations on clinical photographs and study models performed by a group of examiners.

METHODS

Thirty tooth surfaces were selected and assessed clinically, using the visual erosion dental examination system. The chosen surfaces provided the whole range of dental erosions including sound surfaces. The tooth surfaces were photographed and impressions were obtained for preparation of study models. Thirty-three dentists examined and scored the selected surfaces both on photographs and study models.

RESULTS

The quality of diagnosis (AUC, area under curve) was slightly higher using photographs as compared to study models. The difference was statistically significant when the validation criterion was erosion, assuming dentine exposure. The inter-method agreement on photographs and study models versus the clinical evaluation were approximately in the same range with a mean κw of 0.48 and 0.43, respectively. When comparing study models with photographs the mean κw was 0.52. The intra-examiner agreement was strong/substantial for both (photographs mean κw = 0.63 and study models mean κw = 0.60).

STATISTICS

Linear weighted Cohen's kappa (κw) was used to evaluate inter-method and intra-examiner agreement. Receiver operating characteristic and area under the curves were used to express diagnostic quality according to a clinical examination.

CONCLUSION

The results indicated that photographs were as good as study models for recording erosive lesions.

Risk indicators for dental erosive wear among 18-yr-old subjects in Oslo, Norway

The aim was to investigate risk indicators associated with dental erosive wear among 18-yr-old subjects in Oslo, Norway. Of 3,206 adolescents invited to participate in a screening examination for erosive wear, 1,456 were examined (giving a response rate of 45%). As part of the examination all participants completed a self-administered questionnaire. Associations between the presence of erosive lesions and the possible risk indicators were assessed by logistic regression analyses, taking into account the hierarchical relationships between the independent variables. Of all 18-yr-old subjects examined, 38% had at least one tooth with erosive lesions. Multivariate analyses showed significant associations between the presence of erosive wear and being male, brushing teeth once per day or less, episodes of vomiting, daily/weekly episodes of gastro-oesophageal reflux, consumption of fruit juice and sugary soft drinks several times per day, as well as consumption of sugary soft drinks daily to once per week. In conclusion, in addition to gender, dietary habits such as frequent consumption of fruit juice and sugary soft drinks, and the occurrence of reflux and vomiting, appear to be risk indicators for erosive wear. When counselling adolescents at risk, the gender-specific risk indicators should be taken into account.

Dental erosive wear and salivary flow rate in physically active young adults

BACKGROUND

Little attention has been directed towards identifying the relationship between physical exercise, dental erosive wear and salivary secretion. The study aimed i) to describe the prevalence and severity of dental erosive wear among a group of physically active young adults, ii) to describe the patterns of dietary consumption and lifestyle among these individuals and iii) to study possible effect of exercise on salivary flow rate.

METHODS

Young members (age range 18-32 years) of a fitness-centre were invited to participate in the study. Inclusion criteria were healthy young adults training hard at least twice a week. A non-exercising comparison group was selected from an ongoing study among 18-year-olds. Two hundred and twenty participants accepted an intraoral examination and completed a questionnaire. Seventy of the exercising participants provided saliva samples. The examination was performed at the fitness-centre or at a dental clinic (comparison group), using tested erosive wear system (VEDE). Saliva sampling (unstimulated and stimulated) was performed before and after exercise. Occlusal surfaces of the first molars in both jaws and the labial and palatal surfaces of the upper incisors and canines were selected as index teeth.

RESULTS

Dental erosive wear was registered in 64% of the exercising participants, more often in the older age group, and in 20% of the comparison group. Enamel lesions were most observed in the upper central incisors (33%); dentine lesions in lower first molar (27%). One fourth of the participants had erosive wear into dentine, significantly more in males than in females (p = 0.047). More participants with erosive wear had decreased salivary flow during exercise compared with the non-erosion group (p < 0.01). The stimulated salivary flow rate was in the lower rage (≤ 1 ml/min) among more than one third of the participants, and more erosive lesions were registered than in subjects with higher flow rates (p < 0.01).

CONCLUSION

The study showed that a high proportion of physically active young adults have erosive lesions and indicate that hard exercise and decreased stimulated salivary flow rate may be associated with such wear.

Dental erosive wear among Norwegian wine tasters

OBJECTIVE

To assess the prevalence and severity of dental erosive wear among a group of professional wine tasters.

MATERIAL AND METHODS

Eighteen wine tasters currently employed at AS Vinmonopolet, Norway (3 women, 15 men; mean age 39 years) and 30 comparison participants (9 women, 21 men; mean age 39 years) were included in the study. The wine tasters were examined by four calibrated clinicians using the Visual Erosion Dental Examination system. Data concerning medical and dietary history, oral hygiene habits and occupational background were obtained from a self-completed questionnaire. Data were analyzed using Fisher's exact test, and examiner agreement was determined by means of linear-weighted kappa and the intra-class correlation coefficient.

RESULTS

Nine (50%) of the wine tasters and six (20%) of the comparison group showed clinical signs of dental erosion. Among the wine tasters, 39% had dentine involvement, compared to just 7% of the comparison group. The erosive lesions were mainly found on the occlusal surfaces of mandibular first molars in the wine tasters, whereas for the controls, the palatal surfaces of upper centrals were most often affected.

CONCLUSIONS

There was a significant difference in the prevalence of dental erosive wear between the two groups, the wine tasters having a higher prevalence and more severely affected surfaces than the comparison group. Half of the wine tasters had no erosive wear and, for the other half, there was no relationship between the duration of their professional life and the extent of erosive wear.

Reliability of two clinical scoring systems for dental erosive wear

The aim of the study was to evaluate and compare two dental erosive wear scoring systems, the Visual Erosion Dental Examination (VEDE) and Basic Erosive Wear Examination (BEWE). Seventy-four tooth surfaces (photographs) and 562 surfaces (in participants) were scored by 5 (photographs) or 3 (in participants) clinicians using both scoring systems. The surfaces in the photographs were scored twice. The level of agreement was measured by weighted kappa (kappa(w)). Inter- and intraexaminer agreement showed small variations between the examiners for both systems when scoring the photographs. Slightly higher mean kappa(w) values were found for VEDE (kappa(w) = 0.77) compared with BEWE (kappa(w) = 0.69). When scoring the surfaces in the clinical examination the mean kappa(w) values for the two systems were equal (kappa(w) = 0.73). Interexaminer agreement using VEDE was calculated to see how differentiation between enamel and dentine lesions influenced the variability. The highest agreement was found for score 0 (sound, 86%) and score 3 (exposure of dentine, 67%), while the smallest agreement was shown for score 1 (initial loss of enamel, 30%) and score 2 (pronounced loss of enamel, 57%). The reliability of the two scoring systems proved acceptable for scoring the severity of dental erosive wear and for recording such lesions in prevalence studies. The greatest difficulties were found when scoring enamel lesions, especially initial lesions, while good agreement was observed when examining sound surfaces (score 0) and dentine lesions (score 3).