Monitoring lesion activity on primary teeth with CP-OCT and SWIR reflectance imaging.

OBJECTIVE: The purpose of this study was to use cross polarization optical coherence tomography (CP-OCT) and short wavelength infrared imaging (SWIR) reflectance imaging to monitor changes in the structure and activity of early occlusal caries on primary teeth over a period of 6 months during intervention with fluoride. METHODS: Participants (n = 29) aged 6-10 each with two suspected active occlusal lesions on primary teeth completed the study. Fluoride varnish was applied to tooth surfaces every 3-months and participants were instructed to brush twice daily with a fluoride toothpaste. Images were acquired using CP-OCT every 3 months for 6 months. SWIR reflectance images were acquired during forced air-drying of the lesions for 30 s at 0 and 6-months. RESULTS: Most of the 42 lesions appeared initially active at baseline. Only 6 lesions appeared arrested at baseline based on the presence of a highly mineralized transparent surface layer (TSL) in CP-OCT images. At 6 months, 14 of the lesions appeared arrested including the 6 initially arrested lesions and the TSL thickness increased significantly (p < 0.0001). The mean lesion depth (Ld) and the integrated reflectivity over the lesion depth (ΔR) increased significantly (p < 0.05) after 6 months for the 42 lesions analyzed. SWIR reflectance images showed that there was a significantly higher (p < 0.05) delay before changes in intensity were measured for active lesions versus arrested lesions during lesion drying. CONCLUSION: CP-OCT was able to monitor changes in lesion structure and activity including the formation of a highly mineralized TSL indicative of lesion arrest during nonsurgical intervention. Time-resolved SWIR reflectance imaging also shows that there are differences in the dehydration kinetics between active and arrested lesions. This study demonstrates two independent imaging methods that can be used to monitor changes in lesion activity over time.

Comparison of Fracture Strengths among different Commonly Placed Anterior Esthetic Restorations for Primary Dentition: An in vitro study.

The purpose of this study was to determine and compare the shear force (N) required to fracture or dislodge an all-ceramic zirconia-based crown using different luting cement with those of polycarbonate crown and strip crown for the primary anterior teeth in vitro. STUDY DESIGN: Four groups of esthetic restoration for primary anterior teeth were tested for fracture strength: 1) Fifteen all-ceramic zirconia-based crowns cemented with glass ionomer cement, 2) Fifteen all-ceramic zirconia-based crowns bonded with a self-adhesive resin cement, 3) Fifteen polycarbonate crowns cemented with a polymer reinforced zinc-oxide eugenol and 4) Fifteen resin strip crowns. All restorations were placed and cemented on reproductions of dies in an independent laboratory at Delhi, India. All samples underwent loading until fracture or dislodgement with the Universal Testing Machine. The force in Newton (N) required to produce failure was recorded for each sample and the type of failures was also noted and characterized. One-way analysis of variance (ANOVA) test and the Tukey and Scheffe's post hoc comparisons were used for statistical analyses. RESULTS: In this invitro study, results were measured in Newtons (N). Group 1 (410.9±79.5 N) and Group 2 (420.5±57.8 N) had higher fracture strength than Group 3 (330.3±85.6 N) and Group 4 (268.4±28.2 N). These differences were statistically significant at P≤.05 among the sample groups. No significant difference was found between groups 1 and 2 (P = 0.984) nor between groups 3 and 4 (P =0.104). Among type of failures, majority of restoration fractures for zirconia-based crowns and resin strip crowns were due to cohesive failures and polycarbonate crowns had predominantly mixed failures. CONCLUSIONS: Under the limitations of this in vitro study, it could be concluded that all-ceramic zirconia-based crowns attained the highest fracture strength among all restorative samples tested regardless of the type of luting agent employed (P<.01). Cohesive failures were commonly observed in the zirconia crowns and resin strip crowns, whereas polycarbonate crowns revealed predominately mixed failures.

ITGB6 loss-of-function mutations cause autosomal recessive amelogenesis imperfecta.

Integrins are cell-surface adhesion receptors that bind to extracellular matrices (ECM) and mediate cell-ECM interactions. Some integrins are known to play critical roles in dental enamel formation. We recruited two Hispanic families with generalized hypoplastic amelogenesis imperfecta (AI). Analysis of whole-exome sequences identified three integrin beta 6 (ITGB6) mutations responsible for their enamel malformations. The female proband of Family 1 was a compound heterozygote with an ITGB6 transition mutation in Exon 4 (g.4545G > A c.427G > A p.Ala143Thr) and an ITGB6 transversion mutation in Exon 6 (g.27415T > A c.825T > A p.His275Gln). The male proband of Family 2 was homozygous for an ITGB6 transition mutation in Exon 11 (g.73664C > T c.1846C > T p.Arg616*) and hemizygous for a transition mutation in Exon 6 of Nance-Horan Syndrome (NHS Xp22.13; g.355444T > C c.1697T > C p.Met566Thr). These are the first disease-causing ITGB6 mutations to be reported. Immunohistochemistry of mouse mandibular incisors localized ITGB6 to the distal membrane of differentiating ameloblasts and pre-ameloblasts, and then ITGB6 appeared to be internalized by secretory stage ameloblasts. ITGB6 expression was strongest in the maturation stage and its localization was associated with ameloblast modulation. Our findings demonstrate that early and late amelogenesis depend upon cell-matrix interactions. Our approach (from knockout mouse phenotype to human disease) demonstrates the power of mouse reverse genetics in mutational analysis of human genetic disorders and attests to the need for a careful dental phenotyping in large-scale knockout mouse projects.

Oral hygiene practice and home-care challenges in children with autism spectrum disorder in San Francisco: Cross- sectional study.

INTRODUCTION: Autism spectrum disorder (ASD) is characterized by challenges in social interaction, communication, and stereotypical patterns of behavior. They are more likely to have tooth brushing issues and need help with routine dental care. Children with ASD could face difficulty in accessing dental care as the parents have a challenging task in finding a dentist that would treat the child with special needs. As a result, dental care is often neglected. The aims of this study are to evaluate oral hygiene practices and challenges in children with ASD and compare it with typically developing peers (TDP). METHOD: The sample size of the study was 60. Parents of children aged 3-10 were recruited and divided in 2 groups with 30 in each group. Age and gender of children were matched. ASD group included children with medical diagnosis of ASD only and no other co-morbidities. Children in TDP group had no diagnosis of ASD, and reported no disability, or any other diagnosis. Parents were asked to complete the questionnaire which asked about their demographic information, child's oral care regimens, and their knowledge about dental care. Chi-squared tests and t-test were used for statistical analysis. A p-value of .05 was used for determining statistical significance. RESULTS: Many children with ASD (47%) had to travel more than 20 miles for their dental home compared to 13% with TDP (p < .05). Only 60% of children with ASD brushed twice a day with 70% of parents reporting that it is difficult to brush their child's teeth compared to TDP with 93% of children brush twice daily (p < .05). Significantly a smaller number of children with ASD (47%) allowed their parent to brush their teeth as compared to 93% of TSD children (p < .001). CONCLUSION: Parents of children with autism spectrum disorder travel longer distance to find a dental home and face more difficulty in maintaining their child's daily oral hygiene.

Factors Associated with Pre-Dental Students' Intention and Willingness to Serve in the Underserved Community and Vulnerable Population.

A potential solution to the problem of how to increase access to dental care for the underserved and vulnerable populations is to establish an early pipeline of underrepresented and minority college students for a career in dentistry. This study aims to explore factors associated with such pre-dental students' future intentions to serve. A cross-sectional design was utilized with 144 participants completing the questionnaire with four sections, including participants' demographics, experience in access to dental care, psychosocial factors, and intention to serve the underserved and vulnerable populations. Descriptive statistics, chi-squared test, and logistic regression were used for statistical analyses. A positive attitude (OR = 12.03) and higher confidence towards addressing access to dental care issues (OR = 10.43) were found to be the strongest factor for higher intention to serve the underserved and vulnerable populations. Higher knowledge on the prevalence of dental caries among children (OR = 3.18) and participants who experienced difficulty in getting a dental appointment, or finding an available dentist when needed (OR = 3.43), were also associated with higher intention. Identifying key factors associated with higher intention to serve the underserved and vulnerable populations as a future dentist may facilitate workforce recruitment in the Health Profession Shortage Areas (HPSAs).

Pediatric Dental Education Improves Interprofessional Healthcare Students' Clinical Competence in Children's Oral Health Assessment.

Primary care and healthcare providers can facilitate children's timely referral to a dental home. However, there are few studies of providers' oral health knowledge and clinical skills. This study aims to improve future healthcare providers' knowledge, confidence, attitude, and clinical competence in assessing children's oral health. Sixty-five health professional students participated in a 10-week didactic and clinical curriculum on children's oral health. Fifty students completed pre- and post-training questionnaires and were assessed in their knowledge, confidence, and attitude. Calibrated examiners graded students' clinical skills on a 24-point grading criterion. Descriptive statistics, paired sample t-test, and Pearson correlation were used in data analyses. Students were in dentistry (46%), nursing (28%), medicine (22%), and pharmacy (3%). Students significantly improved in knowledge (t = -7.71, p < 0.001), confidence (t = -10.30, p = <0.001), and attitude (t = -4.24, p = <0.001). Students on average scored 83% on clinical competence, with the highest average for fluoride varnish application (96%) and lowest for providing anticipatory guidance (69%). There was a moderate correlation between improvement in knowledge and their clinical skills (r = 0.39, p = 0.010). Interprofessional education improves students' knowledge, confidence, attitude, and clinical competence in assessing children's oral health. Such education is necessary in guiding future providers to gain adequate competence in serving children's oral health needs.

AMBN mutations causing hypoplastic amelogenesis imperfecta and Ambn knockout-NLS-lacZ knockin mice exhibiting failed amelogenesis and Ambn tissue-specificity.

BACKGROUND: Ameloblastin (AMBN) is a secreted matrix protein that is critical for the formation of dental enamel and is enamel-specific with respect to its essential functions. Biallelic AMBN defects cause non-syndromic autosomal recessive amelogenesis imperfecta. Homozygous Ambn mutant mice expressing an internally truncated AMBN protein deposit only a soft mineral crust on the surface of dentin. METHODS: We characterized a family with hypoplastic amelogenesis imperfecta caused by AMBN compound heterozygous mutations (c.1061T>C; p.Leu354Pro/ c.1340C>T; p.Pro447Leu). We generated and characterized Ambn knockout/NLS-lacZ (AmbnlacZ/lacZ ) knockin mice. RESULTS: No AMBN protein was detected using immunohistochemistry in null mice. ß-galactosidase activity was specific for ameloblasts in incisors and molars, and islands of cells along developing molar roots. AmbnlacZ/lacZ 7-week incisors and unerupted (D14) first molars showed extreme enamel surface roughness. No abnormalities were observed in dentin mineralization or in nondental tissues. Ameloblasts in the AmbnlacZ/lacZ mice were unable to initiate appositional growth and started to degenerate and deposit ectopic mineral. No layer of initial enamel ribbons formed in the AmbnlacZ/lacZ mice, but pockets of amelogenin accumulated on the dentin surface along the ameloblast distal membrane and within the enamel organ epithelia (EOE). NLS-lacZ signal was positive in the epididymis and nasal epithelium, but negative in ovary, oviduct, uterus, prostate, seminal vesicles, testis, submandibular salivary gland, kidney, liver, bladder, and bone, even after 15 hr of incubation with X-gal. CONCLUSIONS: Ameloblastin is critical for the initiation of enamel ribbon formation, and its absence results in pathological mineralization within the enamel organ epithelia.

Mutational spectrum of FAM83H: the C-terminal portion is required for tooth enamel calcification.

Dental enamel forms through the concerted activities of specialized extracellular matrix proteins, including amelogenin, enamelin, MMP20, and KLK4. Defects in the genes encoding these proteins cause non-syndromic inherited enamel malformations collectively designated as amelogenesis imperfecta (AI). These genes, however, account for only about a quarter of all AI cases. Recently we identified mutations in FAM83H that caused autosomal dominant hypocalcified amelogenesis imperfecta (ADHCAI). Unlike other genes that cause AI, FAM83 H does not encode an extracellular matrix protein. Its location inside the cell is completely unknown, as is its function. We here report novel FAM83H mutations in four kindreds with ADHCAI. All are nonsense mutations in the last exon (c.1243G>T, p.E415X; c.891T>A, p.Y297X; c.1380G>A, p.W460X; and c.2029C>T, p.Q677X). These mutations delete between 503 and 883 amino acids from the C-terminus of a protein normally comprised of 1179 residues. The reason these mutations cause such extreme defects in the enamel layer without affecting other parts of the body is not known yet. However it seems evident that the large C-terminal part of the protein is essential for proper enamel calcification.

Interprofessional Oral Health Education Improves Knowledge, Confidence, and Practice for Pediatric Healthcare Providers.

Dental caries is the most prevalent chronic childhood disease in the United States. Dental caries affects the health of 60-90% of school-aged children worldwide. The prevalence of untreated early childhood dental caries is 19% for children 2-5 years of age in the U.S. Some factors that contribute to the progression of dental caries include socioeconomic status, access to dental care, and lack of anticipatory guidance. The prevalence of dental caries remains highest for children from specific ethnic or racial groups, especially those living in underserved areas where there may be limited access to a dentist. Although researchers have acknowledged the various links between oral health and overall systemic health, oral health care is not usually a component of pediatric primary health care. To address this public health crisis and oral health disparity in children, new collaborative efforts among health professionals is critical for dental disease prevention and optimal oral health. This evaluation study focused on a 10-week interprofessional practice and education (IPE) course on children's oral health involving dental, osteopathic medical, and nurse practitioner students at the University of California, San Francisco. This study's objective was to evaluate changes in knowledge, confidence, attitude, and clinical practice in children's oral health of the students completed the course. Thirty-one students participated in the IPE and completed demographic questionnaires and four questionnaires before and after the IPE course: (1) course content knowledge, (2) confidence, (3) attitudes, and (4) clinical practice. Results showed a statistically significant improvement in the overall knowledge of children's oral health topics, confidence in their ability to provide oral health services, and clinical practice. There was no statistically significant difference in attitude, but there was an upward trend toward positivity. To conclude, this IPE evaluation showed that offering an interprofessional course on children's oral health to graduate students in dentistry, nursing, and osteopathic medicine can improve their knowledge, confidence, and practice toward children's oral health and expand their professional goals to include caring for underserved, minority children.

Phase Four, Randomized, Double-Blinded, Controlled Trial of Phentolamine Mesylate in Two- to Five-year-old Dental Patients.

PURPOSE: The purpose of this study was to evaluate, using a randomized, double-blind methodology: (1) the safety of phentolamine mesylate (Oraverse) in accelerating the recovery of soft tissue anesthesia following the injection of two percent lidocaine plus 1:100,000 epinephrine in two- to five-year-olds; and (2) efficacy in four- to five-year-olds only. METHODS: One hundred fifty pediatric dental patients underwent routine dental restorative procedures with two percent lidocaine plus 1:100,000 epinephrine with doses based on body weight. Phentolamine mesylate or a sham injection (two to one ratio) was then administered. Subjects were monitored for safety and, in four- to five-year-olds, for efficacy during the two-hour evaluation period. RESULTS: There were no significant differences in adverse events between the phentolamine and sham injections. Compared to sham, phentolamine was not associated with nerve injury, increased analgesic use, or abnormalities of the oral cavity. Phentolamine was associated with transient decreased blood pressure in some children. In four- and five-year-olds, phentolamine induced more rapid recovery of lip anesthesia by 48 minutes (P<0.0001). CONCLUSIONS: Phentolamine was well tolerated and safe in three- to five-year-olds; in four- to five-year-olds, a statistically significant more rapid recovery of lip sensation compared to sham injections was determined.

Assessment of simulated lesions on primary teeth with near-infrared imaging.

Previous studies have demonstrated that the structural changes on enamel due to demineralization and remineralization can be exploited through optical imaging methods such as QLF, thermal and NIR imaging. The purpose of this study is to investigate whether PS-OCT and NIR reflectance imaging can be utilized to assess lesion structure in artificial enamel lesions on the smooth surfaces of primary teeth exposed to fluoride. The smooth coronal surfaces of primary teeth (n=25) were divided into 4 windows: sound, demineralization, demineralization with remineralization and APF with demineralization. Windows were treated with either acidulated phosphate fluoride (APF) for 1 minute, a demineralization solution for 4 days, and/or an acidic remineralization solution for 12 days. The samples were imaged using PS-OCT, QLF and NIR reflectance at 1400-1700 nm wavelengths. This study demonstrated that both PS-OCT and NIR reflectance imaging were suitable for assessing lesion structure in the smooth surfaces of primary dentition.

The dentin phosphoprotein repeat region and inherited defects of dentin.

Nonsyndromic dentin defects classified as type II dentin dysplasia and types II and III dentinogenesis imperfecta are caused by mutations in DSPP (dentin sialophosphoprotein). Most reported disease-causing DSPP mutations occur within the repetitive DPP (dentin phosphoprotein) coding sequence. We characterized the DPP sequences of five probands with inherited dentin defects using single molecule real-time (SMRT) DNA sequencing. Eight of the 10 sequences matched previously reported DPP length haplotypes and two were novel. Alignment with known DPP sequences showed 32 indels arranged in 36 different patterns. Sixteen of the 32 indels were not represented in more than one haplotype. The 25 haplotypes with confirmed indels were aligned to generate a tree that describes how the length variations might have evolved. Some indels were independently generated in multiple lines. A previously reported disease-causing DSPP mutation in Family 1 was confirmed and its position clarified (c.3135delC; p.Ser1045Argfs*269). A novel frameshift mutation (c.3504_3508dup; p.Asp1170Alafs*146) caused the dentin defects in Family 2. A COL1A2 (c.2027G>A or p.Gly676Asp) missense mutation, discovered by whole-exome sequencing, caused the dentin defects in Family 3. We conclude that SMRT sequencing characterizes the DPP repeat region without cloning and can improve our understanding of normal and pathological length variations in DSPP alleles.

Clinical manifestations of terminal osseous dysplasia and pigmentary defects in a young girl.

Terminal osseous dysplasia and pigmentary defects is a rare X-linked dominant disorder with prenatal male lethality. Affected females display multiple systemic abnormalities such as limb deformities and pigmented lesions of the face and scalp. Phenotypic expression of the syndrome varies among the affected individuals. In this case report, we describe the syndromic dental and oral abnormalities in a female child aged 3 and 1/2 years. A widened bigonial width of the mandible and a brachyfacial pattern are observed. Intraoral findings include multiple frenulae, shallow mucobuccal fold, hypodontia, conical incisors, and other developmental structural defects.

International comparisons of health inequalities in childhood dental caries.

OBJECTIVE: To undertake formative studies investigating how the experience of dental caries in young children living in diverse settings relates to familial and cultural perceptions and beliefs, oral health-related behaviour and oral microflora. PARTICIPANTS: The scientific consortium came from 27 sites in 17 countries, each site followed a common protocol. Each aimed to recruit 100 families with children aged 3 or 4 years, half from deprived backgrounds, and within deprived and non-deprived groups, half to be "caries-free" and half to have at least 3 decayed teeth. OUTCOME MEASURES: Parents completed a questionnaire, developed using psychological models, on their beliefs, attitudes and behaviours related to their child's oral health. 10% of children had plaque sampled. RESULTS: 2,822 children and families were recruited. In multivariate analyses, reported toothbrushing behaviours that doubled the odds of being caries-free were a combination of brushing before age 1, brushing twice a day and adult involvement in brushing. Analyses combining beliefs, attitudes and behaviours found that parents' perceived ability to implement regular toothbrushing into their child's daily routine was the most important predictor of whether children had caries and this factor persisted in children from disadvantaged communities. 90% of children with lactobacillus had caries. CONCLUSIONS: Parental beliefs and attitudes play a key role in moderating oral health related behaviour in young children and in determining whether they develop caries. Further research is indicated to determine whether supporting the development of parenting skills would reduce dental caries in children from disadvantaged communities independent of ethnic origin.

Caries experience in children with various genetic sensitivity levels to the bitter taste of 6-n-propylthiouracil (PROP): a pilot study.

PURPOSE: The objective of this pilot study was to determine the prevalence of coronal dental caries among children with different genetic sensitivity levels of taste, as determined by 6-n-propylthiouracil (PROP). METHODS: Coronal caries and restorations in permanent and primary dentition were evaluated in 150 healthy school-aged children aged 6 to 12 years. A filter paper containing 6-n-propylthiouracil was used to determine each subject's genetic ability to taste bitter and sweet substances. Supertasters perceived stronger tastes from a variety of bitter and sweet substances than both medium tasters and nontasters. The data were analyzed by ANOVA with Duncan's multiple range test, Mantel-Haenszel chi-square, multiple linear regression analyses, and Pearson's coefficient of correlation. RESULTS: The nontasters had more mean decayed, missing, and filled surfaces (dfs/DMFS) than tasters. The values of mean decayed and filled surfaces of primary dentition and mean decayed, missing, and filled surfaces of permanent dentition (dfs/DMFS) and mean decayed surfaces of primary dentition and permanent dentition (ds/DS) were significantly higher in nontasters than in medium tasters, and in medium tasters compared with supertasters. After adjusting for missing teeth, the data were expressed as a percentage of the available surfaces, and the significant differences in dfs/DMFS and ds/DS persisted (r = -0.49, P < .001 and r = -0.51, P < .0001 respectively). CONCLUSIONS: After all associated factors were controlled, taste was the only independent variable significantly related to overall caries experience. The results of this study suggested an increased prevalence of overall caries experience in nontaster children.

Oral health education for pediatric nurse practitioner students.

The aim of this study was to evaluate whether an interdisciplinary, multifaceted oral health education program delivered to pediatric nurse practitioner students at the University of California, San Francisco, would improve their knowledge, confidence, attitudes, and behaviors regarding the provision of oral health assessments, consultations, referrals, and services to young children during well-child visits. Thirty pediatric nurse practitioner students were included in the study. Participants completed a written survey before and after receiving an interdisciplinary educational intervention that included didactic education, simulation exercises, and clinical observation by a pediatric dental resident. Between pre-intervention and post-intervention, a significant improvement was seen in the pediatric nurse practitioners' knowledge of oral health topics (p<0.001), confidence when providing oral health counseling (p<0.001), and attitudes about including oral health counseling in their examinations (p=0.006). In the post-intervention survey, 83 percent of the subjects reported having incorporated oral examinations into their well-child visits. Our study suggests that providing an interdisciplinary oral health educational program for pediatric nurse practitioner students can improve their knowledge, confidence, attitudes, and behaviors regarding the incorporation of oral health care services during routine well-child visits.

Mutational analysis of candidate genes in 24 amelogenesis imperfecta families.

Amelogenesis imperfecta (AI) is a heterogeneous group of inherited defects in dental enamel formation. The malformed enamel can be unusually thin, soft, rough and stained. The strict definition of AI includes only those cases where enamel defects occur in the absence of other symptoms. Currently, there are seven candidate genes for AI: amelogenin, enamelin, ameloblastin, tuftelin, distal-less homeobox 3, enamelysin, and kallikrein 4. To identify sequence variations in AI candidate genes in patients with isolated enamel defects, and to deduce the likely effect of each sequence variation on protein expression and structure, families with isolated enamel defects were recruited. The coding exons and nearby intron sequences were amplified for each of the AI candidate genes by using genomic DNA from the proband as template. The amplification products for the proband were sequenced. Then, other family members were tested to determine their genotype with respect to each sequence variation. All subjects received an oral examination, and intraoral photographs and dental radiographs were obtained. Out of 24 families with isolated enamel defects, only six disease-causing mutations were identified in the AI candidate genes. This finding suggests that many additional genes potentially contribute to the etiology of AI.