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Infective endocarditis (IE) is a life-threatening disease, with dental procedures known to produce bacteremia considered to be major factors in its development. Thus, prevention of IE onset with antibiotics given prior to performing dental treatments is widely recommended. However, few studies have been conducted to determine the general knowledge of pediatric dentists regarding IE prevention. Members of the Japanese Society of Pediatric Dentistry were invited to participate in a survey in order to elucidate common knowledge among pediatric dentists for prevention of IE. A total of 118 answered the questionnaire, most of whom had experience with prescribing antibiotics for IE prevention. Approximately 80% of those answered that they administer antibiotics only to patients at high risk for IE, though they also noted difficulties understanding which heart diseases are defined as high risk for the disease. As for dental procedures associated with an increased risk for IE, most of the respondents answered dental treatments conducted as surgical procedures, while less invasive procedures were thought to be low risk for IE. More than 80% of the queried pediatric dentists selected oral amoxicillin at a dose of 50 mg/kg of body weight for child patients. Among those, over 50% prescribed antibiotics only prior to performing dental treatment. We found that pediatric dentists in Japan tend to prescribe antibiotics in accordance with the guidelines, though they expressed difficulty with understanding which heart diseases are at high risk of IE, likely due to lack of training in cardiology.

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.

Hypophosphatasia is a rare inherited disorder characterized by defective bone mineralization and deficiency of tissue non-specific alkaline phosphatase (TNSALP) activity. The disease is caused by mutations in the liver/bone/kidney alkaline phosphatase gene ( ALPL ) encoding TNSALP. As for dental manifestations, premature loss of deciduous teeth due to disturbed cementum formation is well known. However, few reports of multiple cases have been presented. The oral manifestations of patients diagnosed with hypophosphatasia were analyzed by collecting clinical records of cases from a nationwide survey of pediatric dentistry clinics affiliated with 29 university dental hospitals in Japan. We inquired regarding the number of cases and clinical findings of diagnosed patients. We obtained information for 9 children diagnosed with hypophosphatasia from our university and 10 from 6 other universities. The main oral manifestation was early exfoliation of deciduous teeth, which was found in 15 of the 19 cases. Early exfoliation of mandibular deciduous anterior teeth was recognized in 14, whereas there were no cases of early exfoliation of a permanent tooth. The main oral finding of hypophosphatasia was early exfoliation of deciduous teeth, predominantly in the mandibular anterior region of children aged 1 to 4 years old.

Radicular cysts in the primary dentition are rare, with such cysts most commonly occurring in the permanent dentition. Pulpal treatment for teeth affected by dental caries has been suggested as a causative factor of radicular cysts. We report two cases of radicular cysts occurring in the primary dentition after pulpectomy. Marsupialization of the cystic lesion was performed in both cases, resulting in uneventful eruption of the successive permanent tooth. A resin appliance in one case and antibiotic ointment-impregnated gauze only in the other were used to fill and promote healing of the cystic cavity. The results suggest that this approach is effective in inducing complete healing of radicular cysts in the primary dentition and avoiding the formation of residual cysts. Furthermore, use of antibiotic-impregnated gauze appears to offer an easier option than other reported methods in the management of radicular cysts.

We present a case of mesiodens identified in a 1-year 9-month-old boy. The patient visited our clinic after receiving a traumatic injury, which caused intrusion of the maxillary right and left primary central incisors. A periapical radiograph revealed no root fractures, though a mesiodens was incidentally found. The intruded teeth naturally moved into their original positions and periodical examinations were scheduled. At 4Y2M, uncommon mesial inclination of the maxillary right primary central incisor was noted. A radiographic examination showed the enlarged dental follicle of the mesiodens, which appeared to cause the inclination, and we planned fenestration when enlargement of the lesion was identified. At 5Y1M, he received another traumatic injury and the maxillary right primary central incisor was exfoliated. At 5Y5M, the mesiodens spontaneously emerged into the oral cavity and a radiographic examination showed prominent rotation of the maxillary right central incisor. Two-thirds of the crown of the mesiodens could be seen at 6Y4M. At 6Y11M, the patient again received a traumatic injury, and intrusion of the maxillary left primary central incisor was observed. At 7Y0M, the mesiodens and maxillary left primary central incisor were extracted under infiltration anesthesia, after which inclination of the axis of the adjacent maxillary right central incisor gradually improved.

Dental caries in early childhood is a significant public health problem, among which nursing caries is known to be caused by inappropriate nursing habits. The aim of the present study was to investigate lifestyle factors related to nursing caries. We examined 2,506 Japanese children aged 18 months, as a part of public health examinations conducted by the Municipal Public Health Center in 2008. Questionnaires were also administered to their guardians, which focused on nutritional and dental health conditions. Statistical analyses were then performed to determine significant nutritional and dental health factors associated with nursing caries. There were 117 children (4.7% of total) identified with dental caries, of whom 18 (0.7% of total cohort, 15.3% of children with dental caries) were designated as the nursing caries group. Statistical analyses revealed that breastfeeding was the most important factor as compared to children without nursing caries ( P =0.0002; odds ratio, 6.373). Our results showed that inappropriate breastfeeding is one of the most important factors related to both onset and exacerbation of nursing caries, and conclude that parents should be informed of appropriate breastfeeding practices by dentists for their prevention.

Several studies have reported that the prevalence of enamel hypoplasia in pre-term low birth-weight children is higher than that in normal birth-weight children. However, the features of primary teeth dentin in pre-term low birth-weight children are rarely reported. We clinically examined a pre-term very low birth-weight child, and performed histopathological examinations of the extracted primary incisors. Hypomineralized enamel was observed in the permanent upper central incisors, while enamel defects were not detected in primary teeth. In the histopathological examinations, several features of dentin defects, such as irregular dentinal tubules and globular dentin, were observed on the pulpal side of dentin. These findings indicated that dentin formation in the present low birth-weight children was mainly affected during the natal and postnatal periods. Our results provide the evidence that tooth formation in low birth-weight children is affected by postnatal systemic derangement.

Intracoronal resorption in an unerupted developing tooth is rare and most lesions of this type are incidentally found in radiographs taken for other purposes. A 5Y10M-old girl was referred to our clinic by a general practitioner for detailed examination of radiolucency identified in the unerupted mandibular left first permanent molar. Intraoral examination revealed that the affected tooth was unerupted, while the radiographic findings demonstrated a wide radiolucent area in the coronal part of the affected molar, which extended close to the pulp. There were no signs or symptoms associated with the tooth at the first examination. At 6Y4M of age, the affected tooth had emerged into the oral cavity, though the patient reported no symptoms. We performed surgical removal of the gingival tissue corresponding to the occlusal surface of the tooth under infiltration anesthesia and macroscopic appearance showed the affected tooth to be intact. However, when the enamel of the affected tooth was removed, a hollow portion approximately 2 mm into the tooth with no pulp exposure was revealed. Calcium hydroxide was applied to the bottom of the cavity and restoration with cement was performed. Three months after treatment, the patient had no abnormal signs or symptoms. A literature search found 15 similar cases, in which mandibular dentition was more frequently affected than maxillary dentition. As for treatment modalities in those cases, conservative restoration was preferably selected, though extraction was inevitable in approximately half.

A 10Y2M-old girl was referred to our clinic by a general practitioner for consultation regarding an impacted supernumerary tooth identified in the maxillary left incisor region. Our intraoral examination revealed a maxillary left lateral incisor with a tubercle morphology, with slight swelling identified in the labial gingival area between the lateral incisor and primary canine. The dental age of the patient was calculated to be 1 year behind her chronological age based on root formation observed in orthopantomographs. X-ray photographic examinations revealed an impacted tooth on the labial side, with the root apex presumably directed into the palatal side. Computed tomography (CT) was used to produce three-dimensional reconstruction images in order to obtain morphological information for the impacted tooth, which had a tuberculate shape and an appearance that differed from that of the tooth on the opposite side, which showed a typical morphology of a lateral incisor. Periodical examinations were performed thereafter, which confirmed the developmental progress of the root formation of the impacted tooth. At 11Y8M, the tooth had emerged into the oral cavity and was extracted under local anesthesia. Based on this case, we concluded that effective use of CT is beneficial for consideration of treatment modalities in patients with an impacted tooth.

Childhood cancer, such as that manifested by neuroblastoma and hepatoblastoma tumors, is one of the leading causes of death for young children. Chemotherapy is one of the most important approaches available, though it is considered to cause tooth developmental disturbances when patients receive treatment during that period of development. Microdontia, disturbed root development, hypodontia and enamel hypoplasia are reported to be possible late adverse effects of chemotherapy. We analyzed 3 children, for whom chemotherapy had been given for treatment of cancer from the ages of 1 to 2.5 years old. Intraoral examinations revealed microdont of the bilateral maxillary lateral incisors and canines in 1 case, whereas that of the bilateral mandibular first premolars was shown in another. Orthopantomograph examinations revealed congenital absence of the first and second premolars in all 3 cases. The developmental period of the affected teeth in these cases appeared to correspond to the chronological age when chemotherapy was administered.

A 5Y7M-old girl was referred to our clinic by a general dentist for detailed examination of a recurrent gingival abscess in the maxillary left primary central incisor region. An intraoral examination revealed a diffuse swelling in the palatal gingiva area of the affected tooth. A periapical radiograph showed that the affected tooth was actually the primary central incisor and a supernumerary tooth, which had fused and been filled with composite resin at the juncture of the 2 tooth crowns. Removal of the filling induced severe bleeding and root canal treatment was performed. Radiographic examinations revealed 2 independent root canals, thus an additional access cavity to the mesial pulp cavity was produced for further root canal treatment. After the lesion had disappeared, root canal filling was performed using iodoform-calcium hydroxide paste and the affected tooth was restored with composite resin to fashion a single crown. However, the canal filling paste was later observed to be resorbed in the cervical area of the root. At 6Y0M, the patient received a traumatic injury in the anterior teeth region and the fused tooth was drastically displaced in a palatal direction, thus we extracted it under infiltration anesthesia. The root was observed to be wide in the mediodistal direction, and a histopathological examination revealed only dentin between 2 independent root canals. Our findings showed that the fused tooth was composed of 2 crowns and 1 root with 2 independent canals, and indicate that each crown and canal should have been treated separately.

Cerebral gigantism is an overgrowth disorder that occurs from the prenatal stage through childhood and features such clinical symptoms as advanced bone age, macrocephaly, characteristic facial appearance, and learning difficulties. A 4-year 3-month-old girl was referred to our clinic for consultation regarding anterior crossbite and occlusal pain in the molar region. An intraoral examination showed that the mandible was considerably larger than the maxilla. The dental age of the entire dentition estimated from orthopantomogram images was approximately 1 year ahead of chronological age. Cephalometrics analysis demonstrated maxillary protrusion, prominent mandibular protrusion, and vertically severe short face. The size of maxilla was slightly small, whereas that of mandible was above the average. Since height and body weight were above the 97 percentile, the patient was referred to a pediatrician for a general examination prior to dental treatment and diagnosed with suspected cerebral gigantism. As for occlusal pain in the molar region, we considered that it was caused by excessive occlusal pressure. Following application of splinting and several adjustments, the pain gradually disappeared.

We treated a rare case with multiple sites of idiopathic internal resorption in primary dentition. A 3-year-old Japanese boy with no history of medical or dental disorders was referred by a general dentist for management of multiple sites of internal resorption in the primary teeth. Those with internal resorption had a pinkish color, however, no symptoms were noted. An X-ray photographic examination revealed round radiolucent lesions in the crown pulp of the upper right first primary molar, as well as in the roots of the lower right primary canine, upper left central primary incisor, and lower right lateral primary incisor. A histological examination of pulp removed from the right lower lateral primary incisor revealed increases in blood vessels, lymphocytes, and macrophages, while odontoclasts were not identified. Resorption of the teeth progressed rapidly and the lower right primary canine spontaneously exfoliated. Thereafter, endodontic treatment using Vitapex® halted the progress of tooth resorption. Our findings showed that early diagnosis, endodontic treatment, and short-interval follow-up examinations are needed to preserve teeth from rapid internal root resorption.

A case of idiopathic external root resorption identified in a girl aged 4 years and 2 months (4Y2M) is presented. The patient visited our clinic with a chief complaint of spontaneous pain in the area of the lower left primary canine. An intraoral examination revealed severe mobility of the affected tooth, while its marginal gingiva was swollen with a maximum periodontal pocket depth of 5mm. Irrigation of the periodontal pocket and general administration of antibiotics relieved the symptoms within 1 week. However, spontaneous pain recurred in the same area at 5Y0M. External root resorption was found with alveolar bone loss on the distal side, and microbiological analyses using broadrange polymerase chain reaction and sequencing methods were carried out with saliva and subgingival dental plaque specimens. In dental plaque specimens from unaffected regions and saliva specimens, Neisseria and Streptococcus species were frequently identified throughout the observation period. On the other hand, Prevotella and Fusobacterium species were predominant species in the dental plaque specimens from the area of the affected tooth. These results indicate that periodontopathic bacterial species rarely seen in children may have inhabited periodontal pockets formed from external root resorption in the present case.

A case of impacted tooth due to the presence of an odontoma identified in a 5Y7M-old girl is presented. An intraoral examination showed that the maxillary right second primary molar had not emerged into the oral cavity, while a periapical X-ray photograph revealed a small round radiopaque mass with a diameter of approximately 2 mm. The calcified mass was suspected to interfere with eruption of the affected tooth and enucleation of the tissue was carried out under local anesthesia. Histopathological examination results showed that the calcified mass consisted of dental enamel, odontogenic epithelium, and pulp-like tissue, and it was diagnosed as an odontoma. At 6Y1M of age, the tooth had not emerged into the oral cavity due to the possibility of interference in the distal cervical area of the adjacent first primary molar or that of strong tension of the gingiva above the affected tooth. Thus, fenestration of the gingiva over the impacted tooth crown was performed and the tooth crown of the affected tooth appeared in the oral cavity at the age of 6Y6M.

A 10-year-and-4-month old girl was shown to have inverted maxillary right second primary molar and permanent successor teeth, after being referred to our clinic for examination of an unerupted maxillary right second primary molar. Orthopantomograph images taken at the age of 7Y4M showed an impacted maxillary second primary molar and ambiguous tooth germ of its permanent successor, while images obtained at the age of 10Y4M exhibited the tooth germ of the permanent successor in a position on top of the impacted primary molar. Orthopantomographs were obtained twice during the next year, which showed development of the second premolar. The dental age of the entire dentition, except for the maxillary right second premolar, at 7Y4M was considered to be consistent with her chronological age, whereas it was approximately 6 months to 1 year behind of chronological age when determined at the age of 10Y4M, 11Y4M, and 12Y3M. The dental age of the permanent second premolar gradually increased, however, remained approximately 4 years behind chronological age. At 12Y3M, computed tomography examinations were performed to clarify the three-dimensional positions of the second primary molar and its permanent successor. At that time, the impacted primary molar was located close to the inferior part of the maxillary sinus, while the tooth germ of the permanent successor was located in the apex region of the adjacent first permanent premolar and first permanent molar. We decided to carry out the periodical examinations to observe the maxillary right second primary molar and premolar.

We presented a case of an intractable periapical abscess in the area of the maxillary first molar. The tooth had no evidences of dental caries, restoration, or fracture, and responded well to a pulp vitality test. However, a radiographic examination revealed radiolucency in the apical portion of the distal root. Computerized tomography (CT) revealed that the tooth had 1 buccal and 2 palatal roots fused together, expressing a U-shaped. Further, a radicular groove that reached to the crown portion of the distal surface was found. Radiolucency was observed in the area adjacent to the radicular groove and in the U-shaped region. We finally performed an intentional replantation, since conventional periodontic and endodontic procedures were unsuccessful. One year postoperatively, the patient had no clinical or radiographic symptoms.

We treated a case of eruption sequestrum in an 8-year 1-month old boy. The patient first came to our clinic with a chief complaint of discomfort in the mandibular left first molar region. An intraoral examination revealed a small hard tissue fragment on the occlusal surface of the erupting mandibular left first molar, while a periapical radiograph showed a bone-like radiopaque mass. We diagnosed the lesion as eruption sequestrum, and removed it under topical anesthesia. A histopathological examination of the sectioned extirpated tissue showed necrotic cortical bone without osteocytes within the lacunae. Although eruption sequestra are occasionally encountered in daily practice, there is a limited number of reports describing details of specific cases, with only 14 known cases reported in literature. Herein, we report our findings and summarize those in other reports based on clinical, radiographic and histopathological findings.

We present a case of Sotos syndrome. A 2-year-1-month-old Japanese boy diagnosed with Sotos syndrome was referred to our clinic for an oral examination. His growth from birth to the age of 4 years 11 months was pronounced above the 97th percentile. The primary teeth erupted extremely early, with the lower central incisors appearing at the age of 5 months, and all the primary teeth except the lower lateral incisors erupted by the age of 2 years 1 month. In addition, the lower permanent first molar erupted at the age of 4 years 6 months. However, mean dental age did not advance with chronological age. The tooth morphology appeared to be normal, however, the primary teeth were easily degraded by attrition, suggesting the poor calcification. A radiographic examination showed congenital missing of the lower primary and permanent lateral incisors, second premolars, and upper first premolars. In addition, the roots of the primary molars were extremely long and the ration of root length to crown length shown in panoramic radiographs was high.

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.

Four patients with hypophosphatasia, including twin brothers and younger and older sisters, were analyzed longitudinally. Ten periodontitisrelated bacterial species in dental plaque were detected using a Polymerase chain reaction (PCR) method with species-specific sets of primers. Further, clinical parameters related to periodontal conditions were recorded at each visit. One of the twins, who had experienced early exfoliation of the primary teeth, had a greater number of bacterial species than his brother, who had no alveolar bone loss. Both of the sisters experienced early exfoliation of their primary teeth, and the average numbers of tested bacterial species were higher in other subjects of the same age. Our results indicate that impaired cementum tissue caused by hypophosphatasia may produce favorable sites for colonization of periodontitis-related bacteria.

A case of supernumerary primary and permanent canines is presented. A 9Y4M-old boy was referred to our clinic for consultation regarding a maxillary supernumerary primary canine. An oral examination showed 2 primary canines with a similar morphology between the maxillary left lateral incisor and first primary molar. The primary canine in the opposite quadrant had the appearance of a fused-tooth, with composite resin restoration seen in the border. Orthopantomography revealed that permanent successors were present for each primary tooth in the maxillary left region, whereas only a single permanent canine was developing in the opposite quadrant. The 2 primary canines in the maxillary left region were extracted at 9Y4M. The mesially located permanent canine emerged into the oral cavity at 10Y1M and was extracted at 10Y9M. At 12Y2M, the other permanent canine located in the distal position had nearly reached the occlusal plane and the maxillary right permanent canine had arrived at the occlusal plane. Dental age was evaluated by assessing the tooth formation stages in 4 orthopantomographs taken between 8Y5M and 12Y2M, and found to be nearly the same as chronological age. However, the dental ages of the maxillary left permanent canine that had erupted earlier than the one located distally and of the left permanent canine were approximately 1 year behind chronological age. In addition, the dental age of the left permanent canine located distally was 2.5 years behind until the patient reached the age of 10Y9M, after which tooth development was accelerated following extraction of the mesially located permanent tooth.

A case of dense bone island (DBI) in the mandible is presented. A 10-year-1-month-old (10Y1M) girl came to our clinic for dental caries treatment. Radiographic examinations incidentally found an isolated round mass with uniform radiopacity in the region below the mandibular left canine and first premolar, which was diagnosed as a DBI. The patient also had an anterior crossbite and was referred to an orthodontic specialist. Although the orthodontist anticipated that the DBI might cause some problems with tooth movement, there were no specific complications encountered and treatment was completed. Thereafter, periodical examinations were carried out for approximately 8 years from the first visit and there were no adverse condition seen in the affected area. Further, orthopantomographic examinations were conducted approximately every 3 years to monitor the size and radiodensity of the lesion. The lesion expanded by approximately 10% up to the age of 15Y2M, after which it was reduced in size at the age of 18Y3M to become approximately 10% smaller as compared to that at the first visit. Further, radiopacity increased from the first visit to the age of 12Y9M, and then was decreased at the ages of 15Y2M and 18Y3M.

We examined 2 patients with filling material extruded from root canals of their primary teeth that remained for a long time. In Case 1, 3 separate small radiopaque masses were initially identified below the mandibular right second primary molar at the age of 7 years 6 months old and the patient was followed for approximately 7 years. The permanent successor was congenitally absent and the radiodensity of the masses decreased as the patient matured, though they were still apparent 7 years later. In Case 2, a large radiopaque mass was detected in the crown region of the permanent central incisor of a patient aged 5 years 2 months old, which had come from the root canal of the corresponding primary tooth that had been filled with iodoform calcium hydroxide paste. The radiopaque filling material in the root canal and the large mass seen superimposed on the crown of the permanent successor had apparently become separated. The mass became smaller and nearly disappeared 1 year 6 months later. In both cases, the root canal filling materials were speculated to have been extruded from the root apex. Differences in features of the radiopaque masses are discussed in this report.

We present a case of a triple-X syndrome in a Japanese girl who was treated from 5Y9M to 14Y6M of age at the Pedodontic Clinic of Osaka University Dental Hospital. At the first examination, multiple dental caries were identified, and a pulpectomy and extraction of the affected teeth were carried out. There were no congenitally absent teeth, including third molars, though the development of permanent teeth was approximately 2 years behind chronological age. At 14Y6M, a PCR analysis of 10 putative periodontopathic bacteria was performed, and all 10 species were found in saliva samples. At the same time, an oral examination revealed that the gingival tissues were highly inflamed with an extremely large amount of calculus, suggesting a risk for the early onset of periodontitis.

Ameloblastin is one of the extracellular matrix proteins in tooth enamel and may be responsible for autosomal amelogenesis imperfecta (AI), since it plays a significant role in enamel crystal growth. We investigated polymorphisms of the human ameloblastin gene by polymerase chain reaction, DNA sequencing and single-strand conformational polymorphism (SSCP) analysis using genomic DNA from 50 Japanese subjects with sound dentition. One single sequential trinucleotide deletion and 3 single-nucleotide polymorphisms (SNPs) were identified in the translated region. The nucleotide deletion results in the lack of an amino acid residue and 2 of the SNPs cause nonsynonymous substitutions of amino acid residues. These results provide important background information for the investigation of autosomal AI in Japanese patients.

We treated an unusual case of internal resorption of the maxillary left lateral incisor seen in a 15-year-old female. The patient was referred to our clinic complaining of repeated cold pain and spontaneous pain in the maxillary left lateral incisor region. An intraoral examination revealed that the tooth was a microdont with a large tubercle, with a pink spot observed in the mesiopalatal area, while radiograph revealed an unusual radiolucent lesion in the cervical area of the affected tooth. Our diagnosis was internal resorption and the affected tooth symptoms ceased after a pulpectomy was performed. Over the next 3 years, periodical examinations performed at 3-month intervals did not reveal further resorption.

Two cases with severe periodontal inflammation in areas of teeth applied with orthodontic bands are presented. Both were diagnosed as acute periodontitis, and removal of the orthodontic bands followed by professional oral hygiene procedures resulted in the recovery to the normal level of periodontal condition. The presence of 10 targeted species of Gram-negative periodontal bacteria in subgingival plaque samples taken from the corresponding teeth, which were not detected in either patient during the period of severe periodontal inflammation, was assessed several times using a polymerase chain reaction method. As the periodontal conditions of the patients improved, these bacteria were identified during the follow-up examination periods. Our results suggest that none of the 10 Gram-negative periodontal bacteria were associated the acute periodontitis at the teeth applied with orthodontic bands.

Mutans group streptococci play an important role in the formation of dental caries, while mitis group streptococci are considered to be associated with subacute bacterial endocarditis. Both mitis and salivarius group streptococci, which are early colonizers in the human oral cavity, have an effect on the infection and colonization of mutans streptococci. In the present study, a rapid and exact PCR method to detect those oral streptococci was developed using the 16S-23S ribosomal RNA intergenic spacer gene, which is present between 16S rRNA and 23S rRNA within the RNA operon. The PCR analysis was able to correctly identify mutans and mitis group streptococcal species. Our results indicate that the combined PCR analysis method established in the present study is useful for detecting oral streptococcal species, as well as in clinical applications to predict and prevent dental caries and etiological studies of streptococcal infective endocarditis.

Gingival fibromatosis is a rare clinical finding of non-inflammatory gingival overgrowth. Here we present 2 cases of children with gingival fibromatosis and provide a longitudinal analysis of the correlation between the presence of periodontal bacteria and clinical condition. The first case, a boy treated from age 2 to 6, showed periodontitis in the lower anterior region, which recovered to a good periodontal condition by a professional therapeutic approach. The second case is a girl, treated for 2 years from age 10, who presented with extremely enlarged gingiva and severe gingivitis, and a gingivectomy was carried out to eliminate the dental plaque accumulation. In both cases, periodontal bacteria were assessed periodically using PCR (Polymerase Chain Reaction) method, and the results compared with the clinical conditions. In both cases, increased numbers of periodontal bacteria were detected during the bad gingival condition period. In addition, Prevotella nigrescens and Prevotella intermedia were especially detected. Clinical condition seems to be influenced by the number of the periodontal bacteria present, which indicates that an effective monitoring of such bacteria would be beneficial for not only evaluating the current periodontal condition, but also for making an appropriate prognosis of a lesion.

The purpose of the present study was to examine the degree of calcification and the elementary compositions of salivary calculi in children, and to compare the results with those from adults. Two salivary calculi from children and two from adults were used. Each was divided into two parts, one part was examined with a scanning electron microscope (SEM) equipped with an energy dispersive X-ray analyzer (EDAX) and another part with a microradiographic contact device. Calcium, phosphorus, sodium, magnesium, copper, chlorine, silicon, and aluminum could be identified in the salivary calculi from the children using the EDAX. With regard to the ratio of calcium to phosphorus in Kα-wave intensities, there were no statistical differences between the salivary calculi from the children and those from adults. The radiopacities of the salivary calculi from a 4-year-old girl, an 8-year-old girl, a 23-year-old woman, and a 46-year-old man corresponded to 39.8, 42.6, 41.8 and 42.5 μm in aluminum thickness, respectively. There were no statistical differences among them. The findings suggest that salivary calculi from children are similar to those from adults in elements, Ca/P ratio, and radiopacity.

An 11-month-old boy with a talon cusp in the maxillary right primary central incisor is reported. The patient came to our hospital with an abnormal tooth morphology. An intraoral examination showed that 8 teeth had emerged into the oral cavity, among which 1 tooth was identified with the cusp-like structure on the palatal side that extended from the cingulum to the incisal edge and appeared to be T-shaped in the occlusal view. The incisal edge of the affected tooth was displaced labially and the cusp-like structure was located in the dental arch. Since there were no signs or symptoms to be treated immediately, we decided to carry out periodical examinations. As the patient aged, the height of the cusp decreased. The horn-like extended pulp space was identified in radiographs taken at the age of 3Y0M and 5Y5M. There have been no other signs or symptoms of the affected tooth, except for labial displacement, during the 4.5-year follow-up period.

In pediatric dentistry, it is important to continue periodical examinations after the initial treatment as the child continues to grow and develop, and a recall system used for patient follow-up is crucial for effective treatment by pediatric dentists. We developed our own recall system and have used it for more than 25 years. In this study, we evaluated clinical parameters for dental caries and periodontal disease in selected patients, and analyzed the correlation between them and the number of consecutive years each patient participated in recall examinations. The subjects were 9-, 12-, and 15-year-old children who came to our clinic for a periodical examination in the summer of 2005, in whom we analyzed several indices of dental caries and focused on their relationship to number of years of follow-up. There were no significant differences between the number of consecutive years and plaque index among the 3 age groups, though a negative correlation tendency was found in the 15-year-old group. Similar results were found between number of years and the rate of DFT. However, there was a significantly negative correlation between the number of consecutive years of follow-up and DFT scores for first permanent molars in our patients. Our recall system for follow-up examinations, which include brushing practice, diet consultation, and caries preventive treatment (application of fluoride and fissure sealant), was shown to be effective for maintaining the oral health of our pediatric dental patients.

Five cases of delayed eruption of the first molars due to immature tooth formation are presented. Three cases involved a teeth in a single quadrant, two of which were the maxillary left region while the other was in the maxillary right region. Both the maxillary left and right regions were affected in one case, and all four molar regions were affected in another case. Dental age was calculated by evaluating the tooth developmental stage in each case, and was compared with chronological age (CA). The mean dental age, excluding the affected molar region (MD), was compared with the dental age of the affected tooth (DA). The CA was more than 1 SD older than the MD in four cases. When we considered the affected molars to be first permanent molars, DA was 1.51–2.43 years younger than MD in all five cases, while DA was approximately 1.07–2.39 years older than MD when the affected molars were considered as second permanent molars. These results indicated that the developmental stages of the affected molars were between that of the first and second molars, and were estimated to have emerged into oral cavity at an age between 9 and 10 years old.