The aim of the study was to determine eruption sequence between lower first molars and lower central incisors in some Nigerian children. The study population consisted of healthy Nigerian nursery school children in Ibadan, Nigeria. Intra-oral examinations were done out door under natural lightening conditions and only children who had either the lower permanent central incisor(s) or lower first molar(s) were included in the study. Ninety-four children met the inclusion criteria with their mean age at 5.77±0.61 years. Sixty-seven percent of the children were 6 years old, while 23.4% were 5 years old. Only 3.2% were 4 years old. One hundred and seventy six teeth were erupted as at the time of the study. Fifty-seven point ninety-five percent of the erupted teeth were central incisors while 42.05% were lower first molars. It is hoped that the observed reversal in the trend of eruption of the first permanent teeth will afford an opportunity of establishing the trend of dental development in Nigerian children.

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The purpose of this study was to investigate the mutagenic and antimutagenic interactions between several fractions of saliva and the habitual oral bacteria. Antimutagenicity was examined against the known mutagenic substances, 4-nitroquinoline-1-oxide (4NQO), AF-2 and benzo[a]pyrene (B[a]P)), using Salmonella typhimurium strains TA98 and TA100 in Ames test and Rec⁺ and Rec^- strains of Bacillus subtilis of Rec-assay. Four fractions from human saliva, whole saliva, supernatant saliva (Sup), precipitation in saliva (PPT) and heated saliva (Heat), were examined against 4NQO, AF-2 and B[a]P-induced mutagenicity. The whole saliva exhibited the strongest antimutagenic activity amongst all fractions applied against 4NQO and AF-2 in Ames test with more than an 80% inhibition rate. However, the whole saliva had an activity of only 50% inhibition against BP. The potency of the antimutagenicity was in the following order: whole saliva > Sup > PPT > Heat, in Ames test. Rec-assay also exhibited a pattern of antimutagenicity similar to that of Ames test. The cultured supernatants of the oral anaerobic bacteria exhibited a weak mutagenic potency. The cell wall skeletons of the oral anaerobic bacteria exhibited stronger antimutagenic activity against each mutagen than that of the oral aerobic bacteria.

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The aim of this study is to elucidate the root resorption of primary incisors in relation to the development of permanent incisors. We observed the maxillas of the dry skulls of Indian children, using Micro-CT, and measured distance between the root surface of the primary incisor and the bony crypt of the permanent incisor. The bony crypt of the maxillary permanent incisor, which was situated at the lingual side of the primary incisor, grew upward towards the mouth as the tooth eruption stage proceeded. Root resorption was clearly seen at the primary dentition stage, and it proceeded to from root surface towards root canal at the first molar eruption. With the advance of the stage, the distance between the root surface of the primary incisor and the bony crypt of the permanent incisor became shorter, especially the distance between the root of the primary lateral incisor and the bony crypt of the permanent central incisor did. By using Micro-CT, we could confirm more clearly that the growth of the bony crypt of the central permanent incisor deeply influence the progress of root resorption of the primary lateral incisor.

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We surveyed a group of 56 children (aged 2.3-11.3 years) with complete deciduous or mixed dentition who received brushing instruction three times a year at four-month intervals for 3-9 years. The labial, buccal, lingual, and occlusal surfaces of the deciduous dentition were divided into 20 areas, and those of the mixed or permanent dentition were divided into 28 areas. The age at which children were able to consistently reach all these areas was designated as the age at which children were competent enough to brush their own teeth (“the complete practice age”). Until children reach this stage, parents should brush children’s teeth. In this study, the complete practice age was frequently 8-9 years in children who received brushing instruction from before the age of 8 years. However, in children who commenced brushing instruction after the age of 8 years, the complete practice age varied, and an appropriate parental brushing period was difficult to determine. However, no children reached the complete practice age in less than a year after instruction commenced, irrespective of the age that brushing instruction began. Therefore, we suggest that brushing by parents is necessary for at least a year after brushing instruction begins, even in children who begin receiving brushing instruction after the age of 8 years.

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The aim of this study is to evaluate the risk factors for dental caries in young children in Japan. We studied 645 children attending 13 of 30 elementary schools in two areas in Japan. Total salivary level of mutans streptococci and lactobacilli were evaluated at pre-school medical check-ups. Other factors we evaluated included use of fluoride containing dentifrices, administration of fluoride varnish in a private dental office, having regular check-ups, use of mouthwash with fluoride, and daily intake of sweet juice or snacks. Oral examinations were carried out at annual medical check-ups with 2.5 years follow-up and finally 585 children were analyzed. By multivariate logistic regression analysis, only three factors; gender, salivary levels of mutans streptococci and the presence or absence of dental caries in deciduous teeth had a statistically significant correlation with the incidence of dental caries after 2.5 years of follow-up. At age 8, odds ratios were 1.821 for female gender, 1.259 for mutans streptococci (log₁₀ cfu/ml) and 2.262 for dental caries in deciduous teeth. Although the prevalence of dental caries has declined in Japan, mutans streptococci remain a risk factor.

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The aim of the present study was to examine retrospectively how best to treat severe cases of ectopically erupting maxillary canines with mesial angulation exceeding 50 degrees. From the ectopically erupting canines diagnosed at the Pediatric Dental Clinic of Niigata University Hospital, we selected for our study 14 severe cases in which mesial angulation exceeded 50 degrees. Nine ectopically erupting canines could be aligned within the arch after traction, and two canines are in the course of treatment, while three canines were removed. In the removed canines, the vertical length from the occlusal line of the crown top was shorter than that in the aligned canines with similar initial condition. This means that the vertical length to the occlusal line of the impacted canine influences the treatment complexity. In four similar ectopically erupting canines in which mesial inclination was nearly 80 degrees or greater and vertical length was over 30 millimeters with Sector 1 or 2 positioning distal to the midline of the root of its adjacent lateral incisor, the initial disruptive conditions were improved after extraction of the predecessor and/or fenestration of the affected canine. It is concluded that traction should be postponed until a few months after extraction of the predecessor if the ectopically erupting canine is located far away from the occlusal line (over 30 millimeters) and its mesial inclination is more than nearly 80 degrees; also that this treatment plan should be limited to cases in which the crown top belongs to Sector 1 and 2.

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Facial reconstruction is a forensic anthropological technique based on a database of facial soft tissue thickness; however, the information available is generally insufficient to completely reconstruct facial features. While most soft tissue in the craniofacial region is strongly adherent to the bony surface, a few areas, such as the ears, nose, and lip regions, are not. Yet these are vital features for forensic identification and are used in everyday life in facial recognition. For such features, forensic anthropologists investigating age, sex, ancestry, and facial appearance must often rely upon bony information alone. Determination of nasal tip position in adults from the skull has been reported by several researchers. However, data for determining nasal tip position from the juvenile skull have not been reported. The aim of this study was to establish and apply a simple discriminative method of identification of nasal tip location in unidentified juvenile human skeletal remains through an investigation of the cranial base in the current Japanese juvenile population. The result would be applicable for not only the research described above but also estimation of growth of mid facial profile (i.e. estimation of patterns of bony and cartilaginous framework of the nose by diseased palatal clefts etc.) and aesthetic standards. Lateral cephalometric X-ray images were used to measure soft tissue thickness in subjects undergoing orthodontic treatment. Two reference planes were set on the skull radiograph (one had already been set at the beginning of facial reconstruction). After tracing the facial profile and plotting soft tissue and bony landmarks, nine dimensions of distances (length and length ratio) and angles between these landmarks and the nasal tip were measured. A prediction function for the nasal tip was derived from these measurements. This study reports a simple and reliable method of nasal tip prediction for use in forensic facial reconstruction from incomplete human juvenile skulls.

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This report presents a case of Lipogranuloma of lower lip in an 8-year-old boy. The patient has been noticed a painless swelling on his lower lip for about three months. He had a past history of repeated rupture of the lesion, and the lesion currently presented with a soft and nodular mass at the left lower lip. The clinical diagnosis was lipoma. Histopathological examination of the surgically removed specimen revealed a number of fat-like globular material infiltrating into the submucosal tissues including skeletal muscle and atrophic minor salivary gland. A granulomatous inflammation with macrophages was noted over the lipidic infiltration, leading to a final diagnosis of ‘lipogranuloma of foreign body type arising in collapsed mucous cyst’. The lesion was induced by repeating administration of Castor oil on the collapsed mucous cyst in the region. In the present report, we describe a case of lipogranuloma arising in the collapsed mucous cyst caused by Castor oil application, which were very rare of maxillofacial region.

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Gingival fibromatosis is a condition of uncommon gingival overgrowth, with hereditary causes regarded to be associated with the most common form. The condition is generally non-inflammatory, though secondary gingival inflammation occurs in some cases due to formation of anaerobic spaces between gingiva and teeth. We present a case of identical twin brothers aged 11 years 9 months who came to our clinic with complaints of gingival esthetic problems. They were both diagnosed with hereditary gingival fibromatosis and gingivectomies were performed. At 14 years 11 months of age, they returned with gingival swelling, though the inflammation and corresponding conditions were significantly different from those seen at the first visit, as the older twin showed severe gingival inflammation, while the younger had moderate inflammation. A microbiological analysis was carried out using a PCR technique, which specifically identified Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythensis in plaque samples taken from sites of severe inflammation in both patients. The numbers of periodontitis-related species decreased as gingival conditions improved with treatment, including removal of calculus and tooth brushing instruction, and microbiological findings were correlated with clinical conditions. Our findings show that monitoring of periodontitis-related bacterial species is beneficial for evaluating the effects of periodontal treatment with a scientific basis.

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Bilateral dental fusion in the primary dentition is a dental anomaly. However, bilateral fusion of maxillary and mandibular primary central and lateral incisors is very rare. The fused teeth were considered to consist of the bilateral upper and lower primary central incisor and lateral incisor. The maxillary primary central and lateral incisors were joined both on the right and left sides of the arch. Bilateral occurrence of unusually large teeth in the lower incisor region was observed. Radiographically, the maxillary fused teeth were observed to have separate coronary parts. The pulp chambers were separate in case of the upper left fused teeth. The other 3 fused teeth were observed to have a single pulp chamber and root canal. The 4 fused teeth in this case did not include any supernumerary teeth.

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CASE REPORT: A boy visited a local dentist for the treatment of other teeth at the age of 12 years, and the same dentist at the age of 17 years and 6 months. Comparison of panoramic X-rays taken at the age of 17 years and 12 years revealed that the impacted left mandibular canine had transmigrated to the right side, and so the patient was referred to our department for a more detailed examination. The panoramic X-ray obtained at the age of 12 years showed that the left mandibular canine was horizontally impacted almost in the center of the mandibular bone, with its tooth crown oriented toward the right. The panoramic X-ray taken at the age of 17 years and 6 months showed that the apex of the impacted left mandibular canine had horizontally migrated to the tooth root apical area of the right mandibular first molar. CONCLUSION: Transmigration of the mandibular canine across the mandible midline is an uncommon phenomenon. When delayed eruption of primary teeth occurs, it is necessary to confirm the position of permanent tooth germs using panoramic X-rays.

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Dental caries is known to be a multifactorial disease, and patient habits regarding oral hygiene and snacking are considered to be the most important factors in caries development. In this study, tooth brushing and dietary habits associated with dental caries experience were analyzed. Dental caries experience was expressed as decayed and filled permanent teeth (DFT) and primary teeth (dft). The DFT values of adolescent patients (13-15 years of age) recorded in 2006 were significantly lower than those recorded in 2001 (P < 0.01). Next, those who underwent recall examinations in both 2001 and 2006 were analyzed, with attention given to the number of dft in 2001 and DFT increment over 5 years, in addition to relevant tooth brushing and dietary habits. The high dft group (dft 5 or more; n = 43) showed significantly greater DFT increment after 5 years than the low dft group (dft less than 5; n = 39) (P < 0.05). Further, the number of DFT was shown to be significantly lower in subjects who brushed before sleeping every day (P < 0.05). In addition, those who consumed meals and snacks on a regular schedule had significantly lower DFT scores than subjects with an irregular schedule (P < 0.01 and P < 0.05, respectively). These results suggest that dental caries occurrence in young permanent teeth is correlated with that in primary teeth, and instruction regarding good tooth brushing and dietary habits related to the development of dental caries should be provided.

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