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This study examined the water-vapour permeability of thin polymerized resin films fabricated from five co-monomer blends of increasing degrees of hydrophilicity, as measured by their Hoy's solubility parameters. Neat resin films were prepared from five experimental light-curable resins (n = 10). Each film was mounted in a Fisher permeability cup with 8 g of water placed inside the cup. The experiments were conducted in a modified twin-outlet desiccator connected to a vacuum pump in one outlet to permit a continuous airflow to encourage water evaporation. Weight losses by water evaporation were measured at 3, 6, 9, 24, 30, and 48 h by using an analytical balance. Additional resin films were examined by using transmission electron microscopy (TEM) after immersion in ammoniacal silver nitrate. A significant correlation was observed between the cumulative water loss at 48 h and the Hoy's total cohesive energy density (delta(t)). Transmission electron microscopy revealed silver-filled channels along film peripheries and silver grains of decreasing dimensions toward the film centres in co-monomer blends 3, 4, and 5 of increasing hydrophilicity. Hydrophilic dentin adhesives polymerized in thin films are prone to water loss by evaporation. This probably accounts for the water droplets seen on the surface of vital-bonded dentin after the application of simplified dentin adhesives.

To evaluate, by transmission electron microscopy, the extent of silver nitrate penetration into four polymerized resin blends with increasing degree of hydrophilicity after a period of 24 hours.The uncured resin was polymerized in an experimental composite inlay processing chamber under a pressurized nitrogen atmosphere maintained at 551.6 KPa and light-activated for one complete cycle at 125 degrees C for 10 minutes. The resin blocks were sectioned occluso-gingivally into multiple 0.9 x 0.9 x 5 mm resin beams, and immersed in 50% basic, ammoniacal silver nitrate for 24 hours, exposed to a photodeveloping solution and prepared for transmission electron microscopy. The percentage distributions of silver deposits were compared using Kruskal-Wallis one-way analysis of variance (ANOVA) on ranks and Dunn's multiple comparison tests.No silver uptake occurred in the two most hydrophobic resins (Groups 12). The percentage distributions of silver deposits in the more hydrophilic Group 3 (6.23 +/- 1.35%) and 4 (5.08 +/- 1.09%) resins were significantly higher (P0.05) than were found in the more hydrophobic resins but Groups 3 and 4 were not significantly different from each other. The intensity of silver uptake increased with hydrophilicity of the resin blends. TEM examination revealed two types of silver deposits: fine spotted-type silver grains, and islands of interconnecting electron-dense clusters of silver grains. Phase separation of resin components was observed in Group 4 resin blends.

To determine if the in vitro 10-day pH-cycling model used for permanent teeth could be utilized to evaluate de/remineralization effects, on the enamel of primary teeth, of child formula toothpastes.Sound extracted primary anterior teeth were coated with nail varnish, leaving a 1 mm-wide window prior to being placed in a demineralizing solution to produce artificial carious lesions in enamel. The teeth were subsequently cut longitudinally into 100 microm thick sections. The 72 specimens were randomly assigned to six groups. In Set 1 contained the specimens in Group a, which were treated with a pea-sized (0.32 g) quantity of non-fluoride toothpaste (First Teeth), and Groups b and c which were treated with half and pea-sized (0.16 g) quantities of fluoridated toothpaste (Colgate), and cycled for 10 days. The specimens in Set 2 (Groups A, B and C) were similarly treated but subjected to 7-day pH-cycling.After Day 8 the lesions in Set 1 extended into dentin and so could not be evaluated. Polarized light microscopy and microradiography were used to evaluate the lesions subjected to 7-day pH-cycling. Lesions in Groups A and B increased in depth and area by approximately 50%, while those in Group C increased in depth and area by 20%; however, no statistically significant differences occurred between the groups. If this model pH cycling is to be used for primary teeth, a reduction from 10 to 7 days in length should be considered.

The use of oxalate desensitizers on acid-etched dentin prior to adhesive application can result in subsurface tubular occlusion by calcium oxalate crystals. However, the solubility of calcium oxalate increases in acidic solution. We hypothesized that total-etch adhesives can, depending upon their pH, interact with oxalate-desensitizer-treated dentin in an adverse manner. Acid-etched human dentin treated with 2 oxalate desensitizers (BisBlock and Super Seal) was bonded with 4 simplified total-etch adhesives: One-Step (OS), Single Bond (SB), OptiBond Solo Plus (OB), and Prime&Bond NT (PB). Composite-dentin beams were examined by SEM and TEM, both of which revealed numerous spherical globules on OB- and PB-bonded, desensitizer-treated dentin, but not in OS or SB samples. Bond strengths produced by OB and PB were significantly lower in oxalate-treated specimens than those produced by OS or SB. These surface globules may have interfered with hybridization of demineralized dentin with OB and PB resins and caused compromised bond strengths.

One-step self-etch adhesives have restricted use due to their acid-base incompatibility with autocured composites and their behavior as permeable membranes after polymerization. This study examined the feasibility of their conversion to two-step self-etch adhesives via the adjunctive use of a non-solvented, relatively hydrophobic resin coating.iBond, Xeno III and Adper Prompt were used either in multiple coats, or in a single coat followed by the use of a layer of Scotchbond Multi-Purpose Plus bond resin for coupling to light- and auto-cured composites. Four types of experiments were performed. Bonded specimens were examined with TEM after immersion in an ammoniacal silver nitrate tracer. Fluid flow measurements of iBond were conducted using the two application protocols to compare the permeability of the bonded dentin with the original smear layer. Permeability of vital dentin bonded with both application protocols were compared for the transudation of dentin fluid across the bonded dentin. Microtensile bond strengths of dentin bonded with the two protocols were examined for their compatibility with an auto-cured composite.The results of the four experiments were complementary. iBond and Xeno III exhibited "apparent incompatibility" to auto-cured composites that resulted from their inherent permeability. This was confirmed by the presence of dentin fluid transudate on the adhesive surfaces when they were bonded to vital dentin. Conversely, Adper Prompt exhibited "true incompatibility" to auto-cured composites that was caused by adverse acid-base interaction, masking the inherent permeability of this adhesive. "True" and "apparent" incompatibility issues were eliminated upon their conversion to two-step self-etch adhesives.

Water is required to ionize acid resin monomers for demineralization of tooth substrates. We tested the null hypothesis that altering the water concentration in two-step self-etching primers has no effect on their aggressiveness and bonding efficacy to dentin. Five experimental self-etching primers were prepared with resin-water-ethanol volume ratios of 9-0-1, 8-1-1, 7-2-1, 5-4-1, and 3-6-1. They were applied to smear-layer-covered dentin, followed by a bonding resin and composite build-ups for microtensile bond testing and TEM examination of tracer penetration. Increasing water concentration from 0–60 vol% improved acidic monomer ionization that was manifested as increasing hybrid layer thickness. However, significantly higher bond strength was observed in the 7-2-1 group, with minimal nanoleakage in the corresponding hybrid layer. When self-etching primers are formulated, a balance must be achieved to provide sufficient water for adequate ionization of the acidic monomers, without lowering the resin concentration too much, to optimize their bonding efficacy to dentin.

This study examined the extent of organic solvent and water retention in comonomer blends with different hydrophilicity (Hoy's solubility parameter for hydrogen bonding, δ h ) after solvent evaporation, and the extent of tracer penetration in polymerised films prepared from these resins. For each comonomer blend, adhesive/solvent mixtures were prepared by addition of (1) 50 wt% acetone, (2) 50 wt% ethanol, (3) 30 wt% acetone and 20 wt% water and (4) 30 wt% ethanol and 20 wt% water. The mixtures were placed in glass wells and evaporated for 30–60 s for acetone-based resins, and 60–120 s for ethanol-based resins. The weight of the comonomer mixtures was measured before and after solvent evaporation. Resin films were prepared for transmission electron microscopy (TEM) after immersion in ammonical silver nitrate. The percentages of solvent and water retained in the comonomer mixtures, and between the acetone and ethanol groups were measured gravimetrically and were statistically compared. In comonomer-organic solvent mixtures, the percentage of solvent retained in acetone and ethanol-based mixtures increased significantly with hydrophilicity of the comonomer blends ( P 0.05 ). In resin-organic solvent–water mixtures, significantly more solvent and water were retained in the ethanol-based mixtures ( P 0.0001 ), when compared to acetone-based mixtures after 60 s of air-drying. TEM revealed residual water being trapped as droplets in resin films containing acetone and water. Water-filled channels were seen along the film periphery of all groups and throughout the entire resin films containing ethanol and water. The addition of water to comonomer-ethanol mixtures results in increased retention of both ethanol and water because both solvents can hydrogen bond to the monomers.

Objectives. The objective of this study was to report on a novel phenomenon that occurs when resin-modified glass-ionomer cements (RMGICs) are bonded to moist human dentine. Methods. Dentine surfaces from extracted third molars were abraded with 180-grit SiC paper. Ten teeth were prepared for each of the two RMGICs tested (Fuji II LC, GC Corp. and Photac-Fil Quick, 3M ESPE). RMGIC buildups were made according to the manufacturers' instructions. After storage at 37 °C, 100% humidity for 24 h, the bonded specimens were cut occlusogingivally into 0.9×0.9 mm beams. Dentine surfaces bonded with the two RMGICs were examined along the fractured RMGIC/dentine interfaces. Additional beams fractured within the RMGICS and at 3 mm away from the interfaces were used as controls. The fractured beams were examined using scanning electron microscopy (SEM), field emission-environmental SEM (FE-ESEM) and transmission electron microscopy (TEM). Results. SEM and FE-ESEM revealed numerous solid spherical bodies along the RMGIC/dentine interfaces. By contrast, no spherical bodies could be identified within the RMGIC fractured 3 mm distant from the bonded interface. TEM and energy dispersive X-ray analyses performed on carbon-coated ultrathin sections showed that these solid spherical bodies consisted of a thin aluminum and silicon-rich periphery and an amorphous hydrocarbon core within the air voids of the original resin matrix. Conclusion. The spherical bodies probably represent a continuation of GI reaction and poly(HEMA) hydrogel formation that results from water diffusion from the underlying moist dentine. Their existence provides evidence for the permeation of water through RMGIC/dentine interfaces.

To compare nanoleakage patterns of an unfilled (OS; One-Step), a 6 wt% spherical silica-filled (OSs; One-Step Plus) and a 15 wt% glass-filled (OSg) version of a two-step, acetone-based self-priming adhesive. Permeability of bonded dentin treated with OS and OSs was also examined.Deep, coronal dentin from extracted third molars were etched and bonded using these adhesives. One-mm thick sections were immersed in 50 wt% ammoniacal silver nitrate (pH 9.5) for 24 hours. Unstained, undemineralized sections were examined by TEM. The permeability of dentin bonded with OS and OSs were investigated at 20 cm of H2O hydrostatic pressure and compared with the osmotic conductance determined with 4.8 M CaCl2 at zero hydrostatic pressure. Composite-dentin beams bonded with OS, OSs and OSg that were fractured after microtensile bond testing were examined by SEM.Two types of nanoleakage patterns were recognized along the resin-dentin interfaces. The reticular type consisted of discontinuous islands of silver deposits and was exclusively seen in hybrid layers. The spotted type consisted of isolated silver grains and was evident throughout the hybrid and adhesive layers in OS. These two patterns were seen to variable extents in the two filled adhesive versions OSs and OSg and their distribution was independent of one another. OS and OSs bonded dentin were permeable to fluid filtration. However, part of this fluid movement was due to the permeability of the adhesive layer, as demonstrated by osmotic fluid conductance in the absence of hydrostatic pressure. Fractographic analysis revealed denuded collagen fibrils within fractured hybrid layers that were indicative of incomplete resin infiltration.

Van der Woude syndrome is a rare autosomal dominant condition with high penetrance and variable expression. It consists of a cleft lip and/or palate pits on the vermilion of the lower lip, and hypodontia. Two cases of congenital lip pits with cleft lip and alveolus and an isolated cleft palate are described to illustrate the variable presentation of the clinical features and the importance of early recognition of Van der Woude syndrome because of the genetic implications.

Glass-ionomer cements (GICs) are regarded as aqueous gels made up of polyalkenoic acid salts containing ion-leachable glass fillers. The consequence of water permeation across the GIC-dentin interface is unknown. This study used SEM, field-emission/environmental SEM (FE-ESEM), and TEM to examine the ultrastructure of GIC-bonded moist dentin. Dentin surfaces bonded with 6 auto-cured GICs were examined along the fractured GIC-dentin interfaces. Additional specimens fractured 3 mm away from the interfaces were used as controls. SEM revealed spherical bodies along GIC-dentin interfaces that resembled hollow eggshells. FE-SEM depicted similar bodies with additional solid cores. Energy-dispersive x-ray analysis and TEM showed that the spherical bodies consisted of a silicon-rich GIC phase that was absent from the air-voids in the controls. The GIC inclusions near dentin surfaces result from a continuation of the GI reaction, within air-voids of the original polyalkenoate matrix, that occurred upon water diffusion from moist dentin.

This study sought to determine the prevalence of early childhood caries and the oral health habits of children ages 0 to 4 years in Macau, China vs. children in Hong Kong. Caregivers of 353 children from 7 nursery centers completed a questionnaire, and dental personnel examined their children with a light and disposable mouth mirror. The children's mean age was 2.8 +/- 0.6 years. Using the diagnostic criterion that cavitation was evidence of dental caries, the caries prevalence was 18%. When the age range was narrowed to 1.8 to 3.5 years, the caries prevalence was 19% in Macau children compared to 17% in Hong Kong children. No statistically significant relationship existed among caries prevalence, feeding habits, or oral hygiene habits, supporting the notion that the etiology of ECC is multifactorial. The similarity of caries prevalence in these 2 populations may result from the effects of cultural norms on the dental habits of the children.

No data are available on possible risk indicators or the prevalence of caries lesions for preschool children under 4 years of age in Kerala, southern India. Therefore, the aims of this study were: (1) to gather data on caries lesion frequency and distribution; (2) to determine any possible associations with feeding habits and oral health care practices.A sample of 530 children, aged from 8 to 48 months (mean=2.5+/-0.96 years), who attended 13 day care centers were clinically examined for caries lesions using a disposable mouth mirror, tongue spatula, and a torch light. There were 513 dentate children. The caregiver of each child then completed, by interview, a structured questionnaire.Among the group of 252 girls and 278 boys, the dmft was 1.84+/-2.87 with 56% of the children being caries-lesion free. Fifty-nine (12%) were considered to have early childhood caries (ECC), based on the criteria that smooth surface caries lesions on all 4 maxillary incisor teeth indicated severe ECC. Breast-feeding was practiced by 99% of the mothers, and 5% did so exclusively. Generally, breast-feeding was on demand. Statistically significant correlations were found between caries lesions and the child's dental condition, as perceived by the mother or caregiver (P.0001), the dental status of the caregiver (P=.0417), consumption of snacks (P=.0177), giving of sweets as a reward (P.0001), cleaning of the child's mouth (P.0001), oral hygiene status of the child (P.0001) and low socioeconomic status, as measured by income (P.0001).From the results of this study of preschool children in Kerala, the groups at high risk from dental caries lesions are: (1) those with poor oral hygiene status; (2) those who consume snacks and are given sweets as rewards; (3) those belonging to a lower socioeconomic class.

One-step self-etch adhesives behave as permeable membranes after polymerization, permitting water to move through the cured adhesives. We hypothesize that osmotic blistering occurs in bonded enamel when these adhesives are used without composite coupling. Tooth surfaces from extracted human premolars were bonded with 5 one-step self-etch adhesives. They were immersed in distilled water or 4.8 M CaCl2, and examined by stereomicroscopy, field-emission/environmental SEM, and TEM. Water blisters were observed in bonded enamel but not in bonded dentin when specimens were immersed in water. They collapsed when water was subsequently replaced with CaCl2. Blisters were absent from enamel in specimens that were immersed in CaCl2 only. Water trees were identified from adhesive-enamel interfaces. Osmotic blistering in enamel is probably caused by the low water permeability of enamel. This creates an osmotic gradient between the bonded enamel and the external environment, causing water sorption into the interface.

Single-step adhesives which etch and prime simultaneously and are not rinsed should not exhibit areas of incomplete infiltration within hybrid layers produced in sound dentin. This study examined the extent of silver uptake using ammoniacal silver nitrate in three two-step, self-etching primers (Imperva Fluoro Bond, Shofu; UniFil Bond, GC, ABF system, Kuraray) and one single-step, self-etching adhesive (AQ Bond, Sun Medical) bonded to dentin and four poly(HEMA) resins used as controls.Flat dentin surfaces were bonded with these adhesives and sectioned into 0.8-mm-thick slabs that were then coated with nail varnish except for the bonded interfaces and immersed in AgNO3 for 24 h. Four types of poly(HEMA) resins were made: 100% HEMA; 90% HEMA-10% water; 75% HEMA-10% water, all polymerized with TBBO at 50 degrees C for 6 h; 100% HEMA polymerized at 25 degrees C for 30 min. After developing, undemineralized, unstained, epoxy resin-embedded sections were prepared for TEM.Nanoleakage patterns were observed in all bonded specimens. Fine segregated silver particles and reticular silver-staining patterns were found within the thin hybrid layers created by the three self-etching primers. For the single-step, self-etching adhesive, heavy silver deposits were identified within the hybridized complex formed by this adhesive within the smear layer, the underlying intact dentin, and in the adhesive layer. Increasing amounts of silver uptake were observed in poly(HEMA) specimens containing more water or that were polymerized at 25 degrees C for a short time instead of 50 degrees C for 6 h.Silver uptake in hybrid layers formed by self-etching adhesives in sound dentin is not necessarily caused by disparities between the depths of demineralization and resin infiltration. They represent areas of increased permeability within a polymerized resin matrix in which water is incompletely removed resulting in regions of incomplete polymerization and/or hydrogel formation.

Rat incisor teeth exhibit continuous growth, hence they have frequently been used to study the eruption process. The aim of our study was to investigate changes in the eruption rate of impeded and unimpeded rat incisors and to determine if any relationship existed between eruption rate and length of the clinical crown.An image analysis technique was used to measure the length of the mandibular incisors of 23 young female Sprague-Dawley rats, aged 7 to 8 weeks. Over a four-week period, the mandibular right incisors of the 11 rats in the experimental group were shortened every two or three days. Another group of 12 rats served as the control.The mean unimpeded eruption rate was 1.0+/-0.1 mm/day, while the impeded eruption rate was 0.6+/-0.1 mm/day. On day 2, the eruption rate of the unimpeded mandibular incisors accelerated to 163.9% when compared to the controls. The impeded mandibular incisors increased in length by 8.8% and 12.1% for the experimental and control groups respectively. An inverse relationship was identified between the eruption rate and the length of clinical crown of the impeded mandibular incisors, while the unimpeded eruption rate was unrelated to the length difference between the left and right incisors if the length difference exceeded 0.5 mm after accelerated eruption.It was found that the mandibular incisors of young rats need to be shortened every two days in order to study unimpeded tooth eruption, and the shorter the tooth is cut the higher the rate of eruption.

Objective: To investigate the relationship between the presence of demarcated opacities and hypoplasia on permanent teeth and the caries status of the primary predecessor teeth in a cohort of Chinese children. Methods: The study sample consisted of 250 children living in a non-fluoridated area in Southern China whose caries status of primary teeth at the age of 3–6 years had been recorded annually in a previous study. A follow-up examination of their permanent teeth was conducted when they were about 12 years old. The presence of enamel defects was determined by consensus of 2 dentists according to the modified DDE index. Results: 56.8% of the 250 children examined had demarcated opacities, while 10.8% of them had hypoplasia. Demarcated opacities and hypoplasia were found in 5.8 and 1.3% of the teeth examined, respectively. A higher prevalence of demarcated opacities was found in those permanent teeth of which their primary predecessor teeth had caries than in those without (7.5 vs. 3.8%, p < 0.001). A similar finding was obtained for the prevalence of hypoplasia (1.9 vs. 0.4%, p < 0.001). Conclusion: There was an association between caries in primary teeth and the presence of demarcated opacities and hypoplasia in their permanent successors.

Oral-facial-digital syndrome is a group of congenital anomalies, which affects the face, oral structures and digits. There are nine subtypes. OFDS type I, is x-linked dominant trait mostly affecting females. Reports of OFDS type 1 in Asians are extremely rare. This paper shows a case of OFDS type I, in a southern Chinese girl, who in addition to most of the classic features, had fusion of the mandibular canine and lateral incisor teeth.

This study examined the effect of one-bottle adhesives with different acidities on bonding to chemical-cured and light-cured resin composites.Twenty-four non-carious human third molars were divided into eight groups. A flat dentin surface was created for each tooth. Acid-conditioned dentin surfaces were bonded with PrimeBond NT (Dentsply), OptiBond SOLO (Kerr), Single Bond (3M) or One-Step (Bisco). Each adhesive group was covered with composite buildups, using either a light-cured (Z100, 3M) or a chemical-cured composite (BisFil 2, Bisco). Specimens were vertically sectioned into 0.9x0.9 mm beams. Microtensile bond strengths were recorded and failure modes were classified using a stereoscopical microscope. Four representative beams from each group were further prepared for SEM examination.Two-way ANOVA showed that the effect of adhesive types, composite curing modes and their interaction were statistically significant (P0.001). Multiple comparison tests revealed no statistically significant difference in the bond strength of the four adhesives with the light-cured composite (P0.05). However, they were significantly lower when used with the chemical-cured composite (P0.01). A positive correlation was observed between the acidity of adhesives and the bond strengths of the chemical-cured composite. Failure occurred predominantly along the composite-adhesive interface, with microporosities on the adhesive surface and voids within the chemical-cured composite.Air incorporated during mixing of chemical-cured composites only contributed partially to the decreased bond strength observed in simplified-step adhesives. Ultrastructural observations suggested the presence of a surface interaction between the uncured, acidic resin monomers from the oxygen inhibition layer of the adhesive and the initiator components in the chemical-cured composite.

This study examined the in vitro caries inhibiting potential of fluoridated and non-fluoridated rewetting agents that are applied to acid-etched enamel and dentine before the use of a water-free, dentine adhesive.Twelve caries-free premolars were divided into three groups of four teeth each. 2 x 3 x 1.5 mm cavities were prepared on the mesial and distal surfaces of each tooth, with half of the cavosurface margin in enamel and half in root dentine. In Group I (control), One-Step (Bisco, Schaumburg, USA) was applied without etching or rewetting agents. In Group II, cavities were acid-etched, rinsed, dried, and rewetted with Aqua-Prep (Bisco), a non-fluoridated rewetting agent, and then bonded with One-Step. Treatment for Group III was similar to Group II, except that Aqua-Prep F (Bisco), a fluoridated rewetting agent was used. Bonded cavities were restored with a non-fluoride-containing flowable composite (AEliteFlo, Bisco). Artificial carious lesions were induced in these specimens, from which multiple 100+/-20 microm thick longitudinal sections were prepared, yielding 16 specimens per group for evaluation with polarised light microscopy (PLM) and microradiography (MRG). Representative sections were processed for transmission electron microscopy (TEM) examination and scanning transmission electron microscopy/energy dispersive X-ray (STEM/EDX) analyses.The differences in demineralisation of dentine among the groups were not statistically significant for 'relative' lesion depth (p0.05, ANOVA, Student-Neuman-Keuls test), but highly significant for 'relative' lesion area (p0.001). Wall lesions were consistently present in Group I, while inhibition zones were invariably observed in Group III. 87.5% of Group II specimens exhibited neither wall lesion nor inhibition zone. TEM showed that remnant dentine apatite crystallites within the inhibition zones in Group III were larger and denser than those present within the corresponding wall lesions. STEM/EDX analyses confirmed the presence of calcium, phosphorus and fluorine in these plate-like crystallites.When used with a water-free, single-bottle dentine adhesive, a non-fluoridated rewetting agent is able to reduce, but cannot completely prevent recurrent caries. The use of a fluoridated rewetting agent is useful under the situation when microleakage occurs, by providing the additional benefit of fluoride-induced demineralisation inhibition.

BackgroundDental fear and anxiety (DFA) refers to the fear of and anxiety towards going to the dentist. It exists in a considerable proportion of children and adolescents and is a major dilemma in pediatric dental practice. As an Internet social medium with increasing popularity, the video-sharing website YouTube offers a useful data source for understanding health behaviors and perceptions of the public. ObjectiveUsing YouTube as a platform, this qualitative study aimed to examine the manifestations, impacts, and origins of DFA in children and adolescents from the public’s perspective. MethodsTo retrieve relevant information, we searched YouTube using the keywords “dental fear”, “dental anxiety”, and “dental phobia”. Videos in English expressing a layperson’s views or experience on children’s or adolescent’s DFA were selected for this study. A video was excluded if it had poor audiovisual quality, was irrelevant, was pure advertisement or entertainment, or contained only the views of professionals. After the screen, we transcribed 27 videos involving 32 children and adolescents, which were reviewed by a panel of 3 investigators, including a layperson with no formal dental training. Inductive thematic analysis was applied for coding and interpreting the data. ResultsThe videos revealed multiple manifestations and impacts of DFA, including immediate physical reactions (eg, crying, screaming, and shivering), psychological responses (eg, worry, upset, panic, helplessness, insecurity, resentment, and hatred), and uncooperativeness in dental treatment. Testimonials from children, adolescents, and their parents suggested diverse origins of DFA, namely personal experience (eg, irregular dental visits and influence of parents or peers), dentists and dental auxiliaries (eg, bad manner, lack of clinical skills, and improper work ethic), dental settings (eg, dental chair and sounds), and dental procedures (eg, injections, pain, discomfort, and aesthetic concerns). ConclusionsThis qualitative study suggests that DFA in children and adolescents has multifaceted manifestations, impacts, and origins, some of which only became apparent when using Internet social media. Our findings support the value of infodemiological studies using Internet social media to gain a better understanding of health issues.

A system of diagnosing occlusal caries from bitewing radiographs was developed in an attempt to overcome the problems of clinical diagnosis found in other studies. Standardised bitewing radiographs for 1172 Berkshire schoolchildren aged 11–13 years who were participating in a toothpaste trial, were assessed for occlusal caries under uniform magnification and illumination. The radiographic scores were then compared with the clinical records for these subjects. The radiographic technique proved to be acceptably reproducible at 82.6 %. However, only 33.2 % of the lesions present were detected on the radiographs. It is concluded that bitewing radiographs for the detection of occlusal caries are of little value in epidemiological studies.

A randomly selected sample of 662 12-year-old Hong Kong children, 529 of whom were Southern Chinese and 133 non-Chinese, was clinically examined for dental caries. The DMFT values were 2.76 and 1.66 for the Chinese and non-Chinese children, respectively. The D component for the Chinese children was 2.12, while for the non-Chinese children it was only 0.45. Approximately 24.0% of the Chinese children had attended the dentist because they were in pain. Only 3.8% of the Chinese children had sought orthodontic or preventive treatment, compared with 24.0% of the non-Chinese children. Although these findings indicate the caries experience to be well below the FDI/WHO global goal for the year 2000, there is a great need to increase the level of dental awareness among Chinese children.

Clinical examinations of 276 5-year-old children were carried out twice yearly for 2 1/2 years, and a further 1104 11--12-year-old children were examined annually for 3 years. Fifty per cent of permanent first molar teeth had erupted by 6.4 years; the mean age of eruption for permanent second molar teeth was 12.2 years. One year after these mean eruption dates over 10% of first molars and 45% of second permanent molars were already carious. Although development of caries was initially slower in permanent first molars, between the ages of 7.5 and 8.5 years the caries increment rose to 18.8%. By the age of 15 years the DMF was 92% for first and 68% for second molar teeth. The missing and filled proportion of the total DMF rose consistently. This represents the amount of treated caries and exceeded the amount of untreated caries in permanent first molars at all age levels. The rate of caries initiation in the present investigation emphasizes that restorative programmes and preventive regimens for children must be based on frequent recall examinations of not more than 6-monthly intervals.

Summary The left side of the mandible distal to the second primary molar of a 3 years old Southern Chinese boy was resected as a result of osteomyelitis. A diaphyseal clavicular graft pedicled on the sternomastoid muscle was selected for the reconstruction of the mandible. By the age of 6 years, the mandible although stunted in size did exhibit appropriate remodelling. In addition a tooth germ in the region of the second permanent molar was found developing in the autogenous bone graft of the mandible.

Teeth located in the nasal cavity are a rare phenomenon of uncertain cause. A case is presented of such an anomaly found in a patient with a repaired cleft lip and palate. A review of the literature with a discussion of the clinical features, diagnosis, treatment, and etiology is also included.

The value of pictorial criteria for the self-assessment of restorative procedures on primary teeth was evaluated. Part-time clinical teachers and dental students showed improvements in their assessment of restorative procedures when using pictorial criteria. This form of self-assessment in clinical dentistry can be expected to provide the operators with a feedback mechanism which is both evaluative and informative. It indicates whether the response is acceptable or not, and why this is the case. Use of this pictorial form of self-assessment also encourages clinicians to assess their own work critically, thereby raising operative standards.

Randomly selected groups of 486 Southern Chinese and 129 non-Chinese 12-yr-old Hong Kong children were examined for calculus and oral debris. The non-Chinese children had less plaque and calculus than the Chinese children (P less than 0.001). The girls had lower plaque scores than the boys in both ethnic groups. The higher frequency of toothbrushing by the girls possibly reflects their greater awareness of personal appearance. There is a need to increase the standard of oral hygiene and the level of dental awareness amongst Chinese children living in Hong Kong.

The prevalence of enamel defects in Hong Kong is investigated using a randomly selected group of 12-year-olds (TV = 1,069). The numbers and percentages of children with enamel hypoplasia, opacities, and discoloration of one or more teeth are presented, and possible causative agents are discussed. The prevalence of enamel defects in Hong Kong was determined using a randomly selected group of 12-year-olds (N = 1,069). The most common defects were enamel opacities, which occurred in 99.6% of the Chinese children, with 63.4% of them having more than 20 teeth affected. Almost 17% of the Chinese children had disfiguring enamel discoloration, but only one of the non-Chinese children had this defect. The high prevalence of enamel defects may be related to the high frequency of use of tetracycline, metabolic disturbances, and a greater-than-optimal intake of dietary fluoride.

As part of a mixed cross-sectional and longitudinal survey of Hong Kong children which commenced in 1982, 1048 children (539 boys and 509 girls) with a mean age of 12 years 7 months were measured for standing height and weight. Positive secular trends had occurred in the past two decades when the results of this study were compared with those of Chang and his co-workers who performed a survey in 1961-63. At 12 years old, boys were 6.7 cm taller and 5.7 kg heavier, while girls were 4.2 cm taller and 2.9 kg heavier than subjects in 1961-63.

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Background Pre-school children in families of recently settled refugees often have very high rates of early childhood caries (ECC). ECC is associated with a high level of morbidity and is largely preventable, however effective culturally appropriate models of care are lacking. This study aimed to provide a deeper understanding of the refugee experience related to early oral health by exploring pre-school refugee families (i) understanding of ECC and child oral health, (ii) experiences of accessing dental services and (iii) barriers and enablers for achieving improved oral health. The knowledge gained will be critical to the development of effective early oral health programs in refugee children. Methods Community based participatory qualitative methodology using focus groups of resettled refugee families and community refugee nurse interviews. A community reference group was established and a bi-lingual community research associate was employed. Transcripts were analysed for thematic content using NVivo software. Results There were 44 participants: eight focus groups (nine countries of origin) and five interviews. Emergent themes were (i) the major influence of parents’ previous experience, including their beliefs about deciduous (baby) teeth, traditional feeding practices and poverty; and a consequent lack of understanding of the importance of early oral health and early dental caries, (ii) the burden of resettlement including prioritising, parenting, learning about new foods and how to assimilate into the community, and (iii) refugees’ difficulties in accessing both information and dental services, and the role of schools in addressing these issues. An Opportunities for Change Model was proposed. Conclusions The main implication of the study is the demonstration of how enhanced understanding of the refugee experience can inform improvement in early oral prevention and treatment. The community participatory methodology of the study provided a basis for cross-cultural understanding and has already assisted in translating the findings and raising awareness in the provision of targeted refugee oral health services.