The aim of this study was to reevaluate the treatment time of topical application of acidulated phosphate fluoride (APF) solution. Bovine intact enamel was treated with APF solution (pH 3.5, 9,000 ppm F) for 0, 1, 2, 3, 5, and 10 min. Fluoride penetration into the enamel was determined using electron probe micro analyser (EPMA), and the hardness of APF-treated demineralized enamel was evaluated via the micro Vickers technique. Micro Vickers hardness (HV) was significantly different in enamel treated with APF for 1 min and that treated for > 2 min, and also between enamel treated for 2 and that treated for 3 min in samples demineralized for 2 h. No significant difference in the surface roughness (Ra) by confocal laser scanning microscopy was evident at the 3 and 5 min time points. The results of the EPMA analysis, HV, and Ra tests suggest a clinically beneficial effect of APF when applied for 3 min.

抄録全体を表示

The purpose of the present study was to determine whether different consistency of diet and malocclusion induced by the extraction of molar teeth on the masticatory organs modulated gastric acid secretion, gastric emptying and intestinal transit in young and elder rats. Male Wistar rats (young, 5 weeks; elder, 1.5 years) were used in this experiment, and were divided into 2 groups. Group one (G1) was maintained with solid diet, Group two (G2) with mud diet. Further, the mandibular molar teeth of G2 were extracted. The experimental period was 10 weeks. The effect of aging and malocclusion on the parameters of gastric secretion was examined using pylorus-ligated rats. The gastric emptying rate (GER) and small intestinal transit rate was determined in rats by evans blue from the stomach and charcoal from the small intestinal, respectively. In pylorus-ligated rats, Young-G2 rat of gastric juice volume, acid output and pepsin secretion remarkably showed significant decrease in comparison with Young-G1 group, but there was not significant difference between Elder-G1 and Elder-G2. GER of Young-G2 rat group was 44.2 ± 7.9%, significantly lower than that of Young-G1 rat group (61.6 ± 8.8%, P < 0.01), but Elder-G1 rat group were not significantly different than those of rats of Elder-G2 group. In small intestinal transit rates of charcoal meals, G1 and G2 of young were 73.3 ± 9.1 and 55.1 ± 8.6%, respectively, and Elder groups were 61.7 ± 9.8 and 52.6 ± 7.7%, suggesting an insignificant effect on diet. These results suggest that the diet and malocclusion, induced by extraction of mandibular molar teeth of young rat groups, may have a great influence compared to elder rat groups.

抄録全体を表示

The study was carried out to determine oral health status and oral health needs of children presenting at the paediatric neurology clinic of the University College Hospital, Ibadan, Nigeria. Diagnosis of each child’s disability was performed by the Consultant Paediatric Neurologist. Data on socio-demographic characteristics and previous history of trauma to the orofacial structures for each child were obtained and intraoral examinations were done using WHO guide lines. Sixty-one children were diagnosed within the period of study and highest proportion (44.3%) had epilepsy while 41.0% had cerebral palsy. Prevalence of dental caries and trauma were 11.5% and 39.3% respectively while 72.1% had good oral hygiene. Despite the relatively good oral health of the children under study, periodic dental recall appointments will be beneficial in order to supervise and evaluate oral health when early detection and prevention of lesions can be instituted.

抄録全体を表示

PURPOSE: We examined the effects of sweet taste stimulation on pain tolerance threshold (PTT) of oral mucosa in children. SUBJECTS AND METHODS: Subjects comprised 10 children (mean age, 7.3 ± 1.2 years) for whom PTT of oral mucosa was measured 2 min after oral administrations of sucrose or xylitol and water. Sine wave current stimulation (2 kHz, 250 Hz and 5 Hz, SWCS) which can stimulate sensory nerve fiber selectively (Aβ, Aδ and C) was used to measure PTT. RESULTS: Sweet taste stimulation with sucrose or xylitol increased oral mucosa PTT in children, but not in adults. No difference in the increased PTT was seen between sucrose and xylitol. CONCLUSIONS: Oral administration of sucrose and xylitol may potentially relieve pain associated with local anesthetic injections in children.

抄録全体を表示

Lasers are used for various clinical applications in dental practices, and many studies have examined the effects of lasers with different applications on enamel and dentin. The CO₂ laser was introduced into the dental clinic for the removal of caries and for cavity preparation of hard tissues, in anticipation of replacing air turban and micromotor devices. The aim of this study was to examine dentin structural changes by measuring 3-dimensional diameter, depth, and volume in bovine teeth irradiated with a CO₂ laser at 1, 3, or 5 W. According to our measurements, a vaporization depth of 400 μm was created by irradiation for a mere 100 ms in the case of 3 W irradiation and 500 μm in the case of 5 W irradiation. Further, at the same output power, the pulse mode transmitted energy to deeper layers of the tooth as compared with the continuous wave mode, indicating that the pulse mode has more penetrating power than the continuous wave mode. Moreover, the depth of cavity that after laser irradiated was >500 μm at output power 5 W. Thus, irradiation at high output power and the influence of pulse mode on the pulp tissue cannot be disregarded. That is to say, it is important to consider irradiation output power, mode, direction, and distance when lasers are used for adjacent to pulp of tooth that primary incisors and deep cavities.

抄録全体を表示

The purpose of the present study was to propose mathematical models for predicting the normal growth of the upper airway by using the lateral cephalograms. A set of two lateral cephalograms from each sample of 23 normal Japanese children at T1 (4.96 yr. ± 0.74) and T2 (9.47 yr. ± 1.33) was used for the analysis. For the measurements of the upper airway, 14 linear and 1 angular measurements were established. For the evaluation of craniofacial skeleton, 14 linear and 18 angular measurements were used according the traditional methods. The data were analyzed by multiple linear regression analysis. The results revealed 2 possible models for the upper airway growth prediction. The equation for the growth of the height from nasopharyngeal to the oropharyngeal airway space (MPW ⊥ PNS-ANS) is YA = − 22.753 + 0.207X₁ + 0.047X₂ + 0.042X₃, where YA is the annual growth change of MPW ⊥ PNS-ANS, X₁ is the angle N-Pog to SN at T1, X₂ is the angle L1 to mandibular plane at T1, and X₃ is the angle Ramus plane to SN at T1 (R² = 0.692, P < 0.05). The equation for the growth of the height from the nasopharyngeal airway space to GoT-MLPW (MLPW ⊥ PNS-ANS) is YB = 17.025 − 0.075X₄ − 0.047X₅ − 0.075X₆, where YB is the annual growth change of MLPW ⊥ PNS-ANS, X₄ is the angle NSAr at T1, X₅ is the angle ArGoMe at T1, and X₆ is the angle Nasal floor to SN at T1 (R² = 0.773, P < 0.05). The results of the present study could be used as models for predicting growth of the upper airway in the case evaluation and practice of pediatric dentistry.

抄録全体を表示

Presence of pronounced incisal and occlusal wear in primary dentition is fairly common in children. Several factors are implied, however, the possible correlation of craniofacial growth to the occurrence of severe incisal tooth wear in children has not been described to date. Thus, this study was aimed to find any association between the craniofacial growth changes and the occurrence of severe incisal wear in children. MATERIALS AND METHODS: Twenty-seven sets of series of dental casts and corresponding lateral cephalograms are selected from the archive of Pediatric Dentistry, Department of Tokyo Medical and Dental University Hospital. Samples were divided into two groups based on the extent of incisal wear observed on the primary maxillary anterior teeth: slight attrition (N = 13) and severe attrition (n = 14) groups. Lateral cephalograms at early deciduous dentition at T1 (3.5 ± 0.6 years old) and late deciduous dentition at T2 (6.2 ± 0.6 years old) were manually traced and 17 linear and 22 angular measurements were measured with analyzing software (WinCeph ver.9). Annual growth rate for each sample was calculated to determine any significant difference between samples from two groups. RESULTS: Significant horizontal growth of the mandible with both the reduction of anterior tooth height and increase of posterior tooth height were found in the severe attrition group. Reduction of upper incisor angle to FH plane and upper dental arch length were also related with the attrition of teeth. CONCLUSIONS: The incisal tooth wear of deciduous teeth was significantly associated with the craniofacial growth changes.

抄録全体を表示

Fluorescence-based devices are adjunct tools for caries detection. Both DIAGNOdent 2095 (LF) and DIAGNOdent 2190 (LF pen) were developed for this application. The purpose of this in vivo study was to compare the relationship between the measurements obtained using the LF and LF pen devices in primary and permanent teeth. The same sample of occlusal and smooth surfaces caries were evaluated by one examiner using both LF and LF pen devices in children. For occlusal caries, measurements were made at 51 sites in primary teeth, and at 83 sites in permanent teeth. For smooth surface caries, measurements were made at 63 sites in primary teeth, and 163 sites in permanent teeth. The values obtained with the LF pen for occlusal caries in primary and permanent teeth (17.6 ± 2.14, 20.6 ± 1.40, respectively) were significantly higher than those obtained with the LF (9.7 ± 1.24, 11.3 ± 0.78). For caries on smooth surfaces, the values obtained with the LF pen for primary and permanent teeth (8.2 ± 1.22, 7.2 ± 0.45) were higher than those obtained with the LF (4.5 ± 0.57, 3.3 ± 0.23). For both occlusal and smooth surface caries, the values were significantly different between the two devices (P < 0.01). The Spearman’s correlation coefficients comparing the LF and LF pen values for primary and permanent teeth were Rs = 0.87 and 0.86 for occlusal caries and 0.80 and 0.74 for smooth surface caries, respectively. Values from both devices showed high correlation coefficients, indicating similar principle of function. However, the actual values were significantly different, which indicated that the values obtained with the two devices did not agree. The LF pen should be used with caution in patients for whom the LF is already being used to manage caries.

抄録全体を表示

AIM: Fluoride, well known as a specific and effective caries prophylactic agent, also affects the differentiation and function of ameloblasts. High dose sodium fluoride (NaF) induces enamel hypoplasia, also called enamel fluorosis, whereas the size and form of teeth except the enamel are not changed with its treatment. We examined the effects of fluoride on dental epithelium proliferation and differentiation using co-cultures of dental epithelial and mesenchymal cells. METHODS: Cultures of the dental epithelial cell line SF2 and dental mesenchymal cell line mDP were performed, as well as co-cultures. Enamel matrix expression in SF2 cells treated with NaF was analyzed by RT-PCR, while cell proliferation was examined using a trypan blue dye exclusion method and BrdU incorporation findings. The effects of NaF on NT-4-induced ERK1/2 phosphorylation were analyzed by western immunoblotting. RESULTS: Neurotrophic factor NT-4 induced enamel matrix expression, which was inhibited in the presence of NaF. Similar results were observed in regard to SF2 cell proliferation, but not with mDP cells. The levels of proliferation and ameloblastin expression in SF2-GFP cells co-cultured with mDP in the presence of NaF were lower as compared to those in SF2 cells cultured alone. CONCLUSION: Our results indicate that dental epithelial cells co-cultured with dental mesenchymal cells are resistant to the inhibitory effects of NaF on proliferation and ameloblastin expression. They also suggest that the dental fluorosis phenotype may affect enamel, but not tooth size or shape, because of rescue of the inhibitory effects of NaF by culturing with dental mesenchymal cells.

抄録全体を表示

Acidulated phosphate-fluoride (APF) is widely used for the prevention of enamel caries. The topical application of fluoride is a promising treatment for improving the acid-resistance of tooth, promoting its remineralization, and improving its crystallinity. APF contains a high concentration of fluorine ions (9,000 ppm); it first decalcifies the apatite in dentin, generating calcium and phosphate ions, which bind to fluoride ions, thus precipitating calcium fluoride. APF is prepared as an acidic solution (pH 3.5) and is used to reinforce the enamel. However, dentin is less resistant to acid than enamel. As such, APF treatment at the same acidity carries a risk of weakening the dentin after application. In many cases, wedge-shaped defect (WSD), root caries, and attrition can cause dentin exposure, to which the APF can attach. Therefore, in this study, we analyzed the effect of APF treatment on dentin by measuring Vickers hardness, making observations with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), and measuring average surface roughness (Ra). The findings of this study suggested that an acidulated phosphate fluoride (APF) treatment of 3 min or longer caused marked dissolution of dentin and posed the risk of deterioration of its initial strength. Therefore, careful management is required to preclude dentin dissolution when performing APF treatment for preventing dental caries.

抄録全体を表示

Oral and maxillofacial injuries occur frequently during the primary and mixed dentitions, although vertical, complicated fractures involving the crown and root of primary molars are rarely observed during early childhood. Treatment of this type of fracture can be complex, requiring both an early, accurate diagnosis and a precise treatment plan. The purpose of this report was to describe the management of bilateral vertical complicated fracture of mandibular primary first molars associated with trauma in a 2-year-9-month-old girl.

抄録全体を表示

We used the Isolite system for treatment of dental caries identified in a submerged mandibular right primary second molar. A 5-year-6-month-old girl was referred to our clinic for close examination of an impacted mandibular right second primary molar. An intraoral examination showed a slight pit extending inside the gingiva and on the occlusal surface of the tooth. X-ray photographic examination revealed that the affected tooth was severely submerged and had a radiolucent area on the occlusal surface, which extended close to the pulp cavity. Most of the periodontal ligament space could not be clearly identified except for the distal side of the distal root. We considered that the area of the tooth was partially ankylosed and consulted with oral surgeons, who decided to postpone extraction, due to the presence of the permanent successor close to the affected tooth. Thus, we treated the dental caries, which appeared to be technically difficult because of the deep location of the tooth. The Isolite system was utilized in this case, as we considered that adjacent soft tissue and saliva could be excluded with its use. Under infiltration anesthesia, gingival tissue covering the occlusal surface was removed with an electric knife, and the carious lesion was removed, which resulted in pulp exposure. Severe inflammation of the pulp was revealed and pulpectomy was performed. There were no signs and symptoms after the treatment. At 1 year after treatment, the occlusal surface remained exposed and no inflammatory findings were observed in adjacent gingival tissue.

抄録全体を表示

We present three cases of marginal periodontitis with alveolar bone loss due to the presence of a drinking straw-like plastic tube in the periodontal pocket of a lower deciduous incisor. The plastic tube was removed using diamond tweezers in all cases. The results suggest that the symptoms of periodontitis disappear quickly after removal of the plastic tube in such cases and that the affected tooth is normally replaced with the succedaneous tooth. However, while recovering to some extent, the alveolar bone supporting the affected tooth is unlikely to return to normal. This indicates the importance of raising awareness of this problem among dentists and encouraging manufacturers to improve the design and color of such tubes if this type of accident is to be avoided.

抄録全体を表示

Mucormycosis is one of the most rapidly progressing and lethal form of fungal infection in humans which usually begins in the nose and paranasal sinuses. The fungus assaults the arteries leading to thrombosis that subsequently causes necrosis of hard and soft tissues. The purpose of this article is to describe a rare case of maxillary necrosis due to mucormycosis in a 12-year-old diabetic patient and emphasizes early diagnosis and timely management of this potentially fatal fungal infection.

抄録全体を表示