Effects of diabetes on tooth movement and root resorption after orthodontic force application in rats.

OBJECTIVE: To investigate the effects of diabetes on orthodontic tooth movement and orthodontically induced root resorption in rats. SETTING AND SAMPLE POPULATION: Twenty-three 10-week-old male Sprague-Dawley rats divided into control (n = 7), diabetes (n = 9), and diabetes + insulin (n = 7) groups. MATERIALS AND METHODS: Diabetes was induced by administering a single intraperitoneal injection of streptozotocin. Rats with a blood glucose level exceeding 250 mg/dl were assigned to the diabetes group. Insulin was administered daily to the diabetes + insulin group. A nickel-titanium closed-coil spring of 10 g was applied for 2 weeks to the maxillary left first molar in all rats to induce mesial tooth movement. Tooth movement was measured using microcomputed tomography images. To determine the quantity of root resorption, the mesial surfaces of the mesial and distal roots of the first molar were analyzed using both scanning electron microscopy and scanning laser microscopy. RESULTS: After 2 weeks, the amount of tooth movement in the diabetic rats was lower than that in the control rats. Root resorption was also significantly lower in the diabetic rats. These responses of the rats caused by diabetes were mostly diminished by insulin administration. CONCLUSIONS: Diabetes significantly reduced orthodontic tooth movement and orthodontically induced root resorption in rats. The regulation of blood glucose level through insulin administration largely reduced these abnormal responses to orthodontic force application.

Mechanical properties of glass ionomers under static and dynamic loading.

OBJECTIVES: This study evaluated the mechanical properties under static and cyclic loading conditions of various types of glass ionomers used for bases and core build-ups under restorations. METHODS: Compressive strength and three-point flexural strength of two different glass ionomers and two metal-reinforced glass ionomers were determined 1 d after the start of mixing. The flexural fatigue resistance of these materials was measured in the load range of 650 g to 1050 g using a three-point bending machine, and fractured surfaces of the specimens were examined using SEM. RESULTS: All the glass ionomers exhibited similar compressive and flexural strengths. The results analyzed by Cox' proportional hazard model demonstrated that the admixed-type metal-reinforced glass ionomer had the highest fatigue resistance, while the water-hardening glass ionomer had the lowest fatigue resistance among the materials examined (p<0.5). SIGNIFICANCE: There was no significant improvement in the static mechanical properties from incorporating metal particles into the glass ionomers. However, the addition of metal particles as in the admixed-type metal-reinforced glass ionomer produced a material with increased fatigue resistance.

Bond strengths of various materials to dentin using Amalgambond.

This study evaluated the bond strength of four restorative materials to dentin using Amalgambond. Two high-copper amalgams [Tytin; spherical, (T) and Epoque 80; lathe-cute, (E)], a gallium alloy [Gallium Alloy GF (G) and a resin composite [P-50 (P)] were tested. The polished dentin surface was treated with dentin-enamel activator (10 seconds), washed, dried, and adhesive agent was applied (30 seconds). In group A, the dentin adhesive was placed onto the dentin and while still wet, T, E, or G was condensed in cylinders (4 mm diameter) with condensation forces suggested by the manufacturer for a clinical situation. In group B, the cylindrical specimens of restorative material were allowed to set and then adhered to the treated dentin using the adhesive system. For the composite (control), the adhesive was applied to the treated dentin and while still wet, P was layered into the cylinder and cured for a total of 90 seconds. After storage in water (37 degrees C) for 24 hours, all the specimens were tested for tensile bond strength. This study revealed that the bond strength of P was significantly higher than the other materials tested and also that amalgam allowed to set for 1, 6 or 24 hours before adhesion to dentin had a significantly greater bond strength than freshly condensed amalgam. Although the desired high bond strength did not develop in the bonding of the metallic restorative materials, signs of bonding were found.

[Oral complication of sublabial transsphenoidal approach and advantage of endonasal transsphenoidal approach].

In order to know the exact incidence of oral complications due to the sublabial transsphenoidal approach, the authors meticulously heard the complaints of 46 patients, who had undergone the approach more than 3 months before. The incidence of the patients who had one or more complaints concerning the oral region was 52.2%. Dysesthesia of the upper lip was most frequent (37%), followed by upper lip pain (17.4%). These complaints were more marked in two patients who had undergone operations using the sublabial approach twice. Among the nine patients with dentures, the dentures had to be remade in three patients because of gigival atrophy several months after the use of the sublabial approach. With a view to overcoming these complications, the authors adapted the endonasal transsphenoidal approach in 13 patients. There was no inconvenience during surgery while this approach was being used, and there were no postoperative oral complications. Among three patients using dentures, there were none who needed remodeling of their dentures. In nine patients, the tension reducing incision was made in the bottom of the columella, which caused no cosmetic problem. Furthermore, the time consumed for approaching the sphenoid sinus was less than that required when using the sublabial approach. In conclusion, the following type of patient is believed to be an appropriate candidate for endonasal approach. A patient who has a relatively smaller sellar lesion and 1) An acromegalic patient whose nostril is relatively large, 2) An elderly patient using dentures, 3) A patient who has undergone previous transsphenoidal surgery, or 4) A patient whose columellar crease is hidden.(ABSTRACT TRUNCATED AT 250 WORDS)

[Histological study on root resorption of upper permanent incisor].

In the permanent tooth, physiological root resorption does not occur, but inflammatory resorption occurs due to the orthodontic force, ectopic eruption of neighboring tooth and others. In this study, the morphological and histological investigation of the root resorption of the upper permanent incisors caused by the ectopic eruption of the canine was carried out. The left central incisor and lateral incisor from a 12-year-old female were examined. The roots were resorbed almost completely, and in part the resorption extended into the enamel. The results were as follows: 1. In the resorbed dentine, two types of resorption lacuna were observed. One was in direct contact with resorption tissue and the other was repaired with cementum-like tissue. 2. In the resorption lacuna, no odontoclast was recognized. 3. The pulp tissue was normal and the internal resorption was not seen. 4. On the wall of the root canal connected with root resorption, a large amount of hard tissue was formed, and on the external surface of the root, secondary cementum was formed on the primary cementum. 5. Under the scanning electron microscope, the clear dentine tubules in the resorption lacuna, the shallow, unclear resorption lacuna with deposition of the hard tissue and the various steps between them were observed.

[Severe root resorption of maxillary incisors and ectopic eruption of maxillary canine].

A 12-year-old female with severe root resorption in the maxillary left central and lateral incisors (Case 1) and a 27-years-old female with the maxillary left canine erupted in the position of the central incisor (Case 2) were examined and treated. The findings and treatment procedures were as follows: 1. In Case 1, severe root resorption was caused by the ectopic eruption of the canine. On the lingual surface, the resorption had proceeded to a part of enamel. 2. In the Case 1, after the central and lateral incisors were extracted, the canine was carefully guided into the position of the lateral incisor. 3. In Case 2, treatment was not performed, because the chief compliant was carious lesions and the patient did not mind the malposition of the canine. 4. In both Case 1 and 2, the main reason of ectopic eruption of canines was presumably not a discrepancy between the tooth material and the basal arch length but the malposition of the tooth germ and/or abnormal eruption process of the canine.

Cystic lymphangioma: its orofacial manifestations.

A patient age five years, nine months with cystic lymphangioma was studied to determine the causes of malocclusion and the optimum time for its treatment. The main findings were unilateral anterior and posterior crossbite and displacement of the mandibular midline due to maxillary deformity and mandibular rotation. The force of the cystic lymphangioma mass caused deformity of the maxilla and rotation of the mandible. The patient had no functional impairment of speech or mastication. A decision was made to defer treatment of malocclusion until complete surgical excision of the cystic lymphangioma can be undertaken, thereby minimizing the chance of malocclusion re-occurrence.

[Studies on factors causing tooth resorption. 1. Role of prostaglandins as a chemical mediator on resorption of deciduous teeth in rabbits].

The aim of this study was to investigate the effects in the administration of indomethacin which is a specific inhibitor of prostaglandins (PGs) in order to understand the role of PGs in physiologic root resorption. For this study, 24 young rabbits aged 7 days which had been in utero for 31-32 days were used. The experimental group (N = 12) was injected with 5.0 mg/kg indomethacin every 12 h, and the control group (N = 12) was injected with normal saline solution every 12 h. 4 animals of each group were sacrificed at the 9th, 11th and 13th day, respectively. Their maxillary deciduous incisors embedded in paraffin were sectioned serially 7 mus in thickness. From each sample was counted the number of odontoclasts appearing on the root surface and measured the volume of the root in the maxillary deciduous incisor. The results were as follows: 1. The appearance of odontoclasts increased in a day-related manner from 9 days to 13 days on the resorption of maxillary deciduous teeth in the control and experimental rabbits. 2. The number of odontoclasts was significantly decreased by the administration of indomethacin (9 days P less than 0.05, 11 and 13 days P less than 0.01). 3. The amount of the root resorption was significantly inhibited by the administration of indomethacin at 9 days which was the initial stage of root resorption in the maxillary deciduous incisors, and then the effect of inhibition rapidly disappeared. These results strongly suggest that PGs can possibly act as a chemical mediator of odontoclastic root resorption occurred during tooth exchange.

[Dentofacial manifestations in children with vitamin D-dependent Rickets type II].

Calcification of the teeth, size of the teeth and dental arches, facial growth and calcification of the carpal bones were studied in three children with clinically different severities of vitamin D-dependent rickets (DDR), type II, with alopecia, which is 1,25-dihydroxyvitamin D-receptor-defect rickets and is particularly resistant to treatment with calciferol analogues. They were treated in a pediatric clinic with large doses of 1 alpha-hydroxyvitamin D3(1 alpha-(OH)D3) and 2 g/day of calcium lactate. The results were as follows: 1. Hypoplasia of enamel of the deciduous teeth was not found. 2. In the deciduous teeth, large pulp chambers and thin dentin were seen in radiographs before treatment. In patients 1 and 2, these abnormalities were reversed by treatment. In patient 3, who had the severest manifestations, large pulp chambers and thin dentin decreased but still remained. 3. Growth of permanent teeth was retarded before treatment and during resistance to treatment. After effective medication, it caught up and was corrected. 4. Problems concerning maxillary and mandibular growth were not found. However Nasions of three patients were more front and lower and Orbitals were lower than standard. 5. In patients 1 and 2, the calcification of carpal bones was accelerated and in patient 3 retarded. 6. Mesiodistal dimensions of erupted deciduous and permanent teeth were within the standard range, except for patient 3, who had smaller lower deciduous teeth. 7. A ground section of the extracted upper right first deciduous molar from patient 3 showed abundant inter-globular dentin and lack of pre-dentinal layer. From the above findings, it was felt that in all probability dentinogenesis was disturbed by the DDR type II. Abnormally large pulp chambers and thin dentin could be corrected by effective medication. In patients with vitamin D-dependent rickets type II, oral hygiene for caries prevention is the most important procedure, because the pulp will be infected immediately after initiation of dental caries. After effective medication, permanent teeth and jaw bones will probably grow normally.

[Effects of mastication on the growth and development of salivary glands in male mice].

Mastication has attracted considerable attention in recent years for its effects on the postnatal growth and development of the mandible, brain, salivary glands and other organs in children. In this study, the relationship between mastication and growth and development of the salivary glands was examined, because the salivary glands are rich in growth factors and many kinds of biological polypeptides, and have endocrine and exocrine actions and effects, on the growth and metabolic rates in developing animals. The experiment utilized two groups of male mice, a control group fed a solid diet, and an experimental group receiving the paste diet ad lib. In the experimental group fed the paste diet, the increase of the tissue weights and the contents of DNA and RNA in the parotid and submandibular glands were lower than those of the control group. Also the rise of amylase activity in the parotid glands was depressed. Next, the polyamine metabolism in the parotid and submandibular glands was examined. The activities of the late limiting enzymes in polyamine syntheses, ornithine decarboxylase and S-adenosylmethionine decarboxylase and the lev- putrescine and spermidine in both parotid and submandibular glands were in the experimental group. These results suggest that mastication plays an important roles in the growth development of the parotid and submandibular glands in mice.

[Studies on factors causing tooth resorption. 2. Dose-response effects of indomethacin on resorption of deciduous teeth in rabbits].

The aim of the present study was to confirm whether prostaglandin (PGs) had any connection with physiological root resorption. 16 young rabbits aged 7 days which had been in utero for 32 days were used and were divided into 4 groups. The control group was injected with normal saline solution, and the experimental groups were injected with indomethacin, a specific inhibitor of PGs synthetase, in doses of 0.1 mg/kg, 1.0 mg/kg, 10.0 mg/kg every 12 hours for 5 days, respectively. All animals were sacricfied at 11 days postnatal. Their maxillary deciduous incisors were embedded in paraffin and sectioned serially in 7 mus thickness. The number of odontoclasts appearing on the root surface were counted, and the volume of the maxillary deciduous incisor was measured. The results were as follows: 1. The readings of the odontoclasts appearing in the control group was 260.3 +/- 60.1, and those of the experimental groups injected with 0.1 mg/kg, 1.0 mg/kg, 10.0 mg/kg indomethacin were 249.0 +/- 32.2, 199.5 +/- 15.1 (P less than 0.05 one sided test) and 163.8 +/- 40.0 (P less than 0.01), respectively. The number of odontoclasts was reduced linearly as the logarithmic dose of indomethacin increased. 2. As far as the volumes of the maxillary deciduous incisors were concerned, that of the group with 10.0 mg/kg was significantly greater than that of the group with 0.1 mg/kg (P less than 0.05). In comparison with the control and the experimental group, the volume of the 10.0 mg/kg group was greater than the others, but statistical differences were not found.

[Dentigerous cysts of children treated by cyst wall enucleation. Report of eleven cases].

The present paper describes ten children with eleven cases of dentigerous cysts which were treated by extraction of the primary teeth, cyst wall enucleation and lingual-arch spacemaintainer. The patients were seven boys and three girls, with a mean age of nine years two months, in Hellman's Dental Age IIIA and IIIB. In eight of the cases, the mandibular second premolar was involved, and of the remainder, two cases involved the first premolar, and one case, a maxillary lateral incisor. In eight out of the eleven cases, the pulp of the primary tooth had been treated. Radiographically, nine cases exhibited a pericoronal space of 15 mm-35 mm and two cases 50 mm-55 mm. The material for histological examination, typically, gave the appearance of a stratified squamous epithelium showing chronic inflammation. Healing took place more rapidly than routine marsupialization. In eight cases the successor erupted in the normal position without orthodontic treatment, in two cases with light orthodontic power. In one case the behavior of the permanent tooth was kept under observation. From the above, this approach to treatment by cyst wall enucleation and lingual-arch spacemaintainer would appear to be very useful for the young child.

[Effect of epidermal growth factor (EGF) on proliferation of the cells derived from the root resorbing tissue of human deciduous teeth].

The resorption of the roots of deciduous teeth is a physiological phenomenon. Many morphological and histological investigations of the root resorption have been reported. However little biochemical data concerning systemic factors in it are available. In this study, cell culture derived from the root resorbing tissue of human deciduous teeth was tried and the effect of EGF on that cell was examined. The dissected root resorbing tissue from human deciduous teeth was cultured in a medium containing 10% fetal calf serum in a humidified incubator at an atmosphere of 5% CO2 in air at 37 degrees C. The outgrowing cells from root resorbing tissue were a mixed population of mesenchymal cells and epithelial cells during the early stage of cultivation, but at the later stage they changed to morphologically single population. The mesenchymal cells seemed to be derived from the dental sac and the epithelial cells from the enamel organ or the oral mucoepithelium. These cells seemed to be useful for analysis of the systemic factors in the root resorption. The effect of EGF on the proliferation of cells obtained as stated above was examined. EGF markedly stimulated DNA synthesis about by a factor of 6.9 for the mesenchymal cells and by a factor of 3.4 for the epithelial cells. These results suggested that EGF participates in the root resorption of human deciduous teeth.

[Studies on the cooperation-enhancing approach in dealing with children in the dental setting. 4. Relationship between adaptability to dental treatment and behavioral and emotional reactions before and during treatment].

The correlation between the behavioral and emotional reactions before dental treatment and the adaptability to dental treatment was evaluated in 84 three-to-six-year old children. Also the physical behavior of the children, the verbal reaction of the children and the speaking of dentists to the children during treatment were investigated among 13 cooperative and 13 uncooperative three-to-six-year old children. Dental treatment was conducted with tooth brushing, surface anesthesia, infiltration anesthesia, rubber dam application, cavity preparation with air turbine, cavity preparation with electric motor and composite resin filling. The results are summarized as follows: 1. There was a significant correlation between twelve of the twenty behavioral and emotional reactions before treatment and the adaptability to dental treatment. 2. The children who showed an uncooperative behavior to dental treatment showed a higher score of physical behavior during each treatment than the children who showed a cooperative behavior to dental treatment. 3. The score of physical behavior increased as the treatment progressed from tooth brushing to infiltration anesthesia. Among the children who showed cooperative behavior, the score showed a peak at the infiltration of anesthesia and then decreased. On the other hand, the children who showed uncooperative behavior continued showing a high score. 4. The uncooperative children showed a higher frequency of verbal reaction and crying than the cooperative children. 5. The frequency of speaking of the dentist to the uncooperative children was one and a half times as much as to the cooperative children. More than sixty percent were "instructions" and "explanations" to both of the cooperative and uncooperative children. "Praise" was used more to the cooperative children, and "count 10" and "encourage" were used more to the uncooperative children.

[Hypoplasia of tooth in children with inborn errors of metabolism].

For the investigation of the clinical dental manifestations of inborn errors of metabolism, the oral examination of twenty one children aged from 5 months to 15 years 5 months was performed at the pediatric clinic of inborn errors of metabolism. The results were as follows: 1. In six of seven histidinemia patients, white spots, pit or hypoplasia of enamel, fused teeth, peg teeth or abnormal tubercles were observed. 2. In a patient with GM1-gangliosidosis, the upper and lower central incisors had severe white spots. 3. In one patient with osteopetrosis, one of two glycogenosis type IX and one of two homocystinuria patients, white spots or hypoplasia of enamel were observed. 4. One patient with hypophosphatemic vitamin D-resistant ricket, one with vitamin D-dependent ricket type II and one with galactosemia patient had no enamel hypoplasia. It was strongly suggested that there is a specific relationship of histidinemia and GM1-gangliosidosis to dental manifestations.