OBJECTIVETo study the dental caries status of the 65-74 years old people in northeast of China, analyze the distribution of caries in the group of people, and provide scientific basis for establishing the oral health care policies.

METHODSThe representative samples were selected by multi-stage, stratified and random sampling from the three province of northeast of China. Dental caries of 2 364 people aged 65-74 were recorded according to WHO criteria. SPSS 12.0 software was used to analyze the data.

RESULTS1) Among 2,364 elderly people in northeast of China, the prevalence of dental caries was 67.5% and DFT was 2.68, the composition of filling was 10.82%. 2) The prevalence of coronal caries was 66.4% and DFT was 2.55. The composition of filling was 11.37%. 3) The prevalence of root surface caries was 48.4% and DFT was 1.64. The composition of filling was only 1.8%.

CONCLUSIONThe prevalence of dental caries among elderly people in northeast of China is still very high, and the filling rate is low. The community based oral health promotion should be strengthened and preventive-oriented oral health care systems are needed in northeast of China.

Aged ; China ; Dental Caries ; Humans ; Prevalence ; Risk Factors ; Root Caries

Straight access cavity design allows the operator to locate all canals, helps in proper cleaning and shaping, ultimately facilitates the obturation of the canal system. However, change in the fracture strength according to the access cavity designs was not clearly demonstrated yet. The purpose of this study was to determine the influence of different access cavity designs on the fracture strength in endodontically treated mandibular anterior teeth. Recently extracted mandibular anterior teeth that have no caries, cervical abrasion, and fracture were divided into three groups (Group 1 : conventional lingual access cavity, Group 2 : straight access cavity, Group 3 : extended straight access cavity) according to the cavity designs. After conventional endodontic treatment, cavities were filled with resin core material. Compressive loads parallel to the long axis of the teeth were applied at a crosshead speed of 2mm/min until the fracture occurred. The fracture strength analyzed with ANOVA and the Scheffe test at the 95% confidence level. The results of this study were as follows : 1. The mean fracture strength decrease in following sequence Group 1 (558.90 +/- 77.40 N), Group 2 (494.07 +/- 123.98 N) and Group 3 (267.33 +/- 27.02 N). 2. There was significant difference between Group 3 and other groups (P = 0.00). Considering advantage of direct access to apical third and results of this study, straight access cavity is recommended for access cavity form of the mandibular anterior teeth.
Axis, Cervical Vertebra ; Root Caries ; Tooth*

The purpose of this study was to evaluate the abrasion-resistance of root surface after NaF iontophoresis, Nd:YAG laser irradiation and combined treatment 50 anterior teeth with flat interproximal root surface that had been extracted due to periodontal destruction were selected. All teeth were treated by the same procedure as conventional periodontal root treatment, such as scaling and root planing, root conditioning with tetracycline HCl(100mg/ml, 5min). The pre-treatment weight of each tooth was measured by a dial scale(SHIMADEU Co., LIBROR EB-220HU, capacity 220.000 g, Japan). All teeth were divided into 5 groups as follows; Nd:YAG laser irradiation(group 1, 1 W, 100 mJ, 10Hz, fiberoptic-root surface distance=5mm, 10 sec.x6times, EL.EN.EN060, Italy); NaF iontophoresis(group 2, 150micronA, 4 min.); Nd:YAG laser irradiation following NaF iontophoresis(group 3); NaF iontophoresis following Nd:YAG laser irradiation(group 4); No treatment(control group). Electric toothbrushing (Oral-B, Brown Co., Germany) was conducted during 1 hour(10 min.x6 times). Subsequently post-treatment weight was remeasured by the same method as pre-treatment weight measurement. The difference of abrasion rate among all groups was statistically analyzed by ANOVA(SAS program). Following results were obtained; 1. The abrasion rate was significantly lower in Nd:YAG laser irradiation group than NaF iontophoresis group(p < 0.001). 2. The abrasion rate was significantly lower in combined groups of Nd:YAG laser irradiation and NaF iontophoresis than either Nd:YAG laser irradiation group or NaF iontophoresis group(p < 0.001). 3. There was no significant difference in abrasion rate according to application order in the combined groups(p > 0.05). 4. The abrasion rate was significantly lower in all experimental groups than control group(p < 0.001). The results suggest that combined treatment of Nd:YAG laser irradiation and NaF iontophoresis on exposed root surface after periodontal therapy can enhance the abrasion-resistance of root surface and may inhibit the root caries development.
Iontophoresis* ; Root Caries ; Root Planing ; Tetracycline ; Tooth ; Toothbrushing

OBJECTIVETo investigate the genotypic diversity of Actinomyces naeslundii in aged people and the relationship between the genotypes of Actinomyces naeslundii and root caries.

METHODSAccording to the inclusion criteria, 20 aged people with root caries and 20 without root caries were chosen into two groups for this study. Two sites were chosen in subjects with root caries: One site was the exposed sound root surface, and the other site was the root caries. In subjects without root caries the sampling site of root surface was exposed. Bacteria were cultured and then identified. Repetitive extragenic palindromic sequence-based polymerase chain reaction (REP-PCR) was used to analyze the genotypic diversity of the Actinomyces naeslundii clinic isolates.

RESULTS299 strains were isolated from the groups, 156 strains were chosen to analyze, belonged to 61 different genotypes. At the site of sound root surface in the subjects with root caries, there were 57 strains with 25 different patterns. At the site of root caries and of sound root surface in subjects without caries, there were 34 strains with 25 different patterns and 65 strains with 26 different patterns respectively. There was the genotypic diversity within Actinomyces naeslundii. There was significant difference in the genotypes in every individual site.

CONCLUSIONMany different genotypes of Actinomyces naeslundii concerned with occurrence of root caries.

Actinomyces ; Aged, 80 and over ; Dental Caries ; Genotype ; Humans ; Polymerase Chain Reaction ; Root Caries ; Tooth Root

Distal caries of the second molar is common indication for the mandibular third molar surgery and there are no universally acceptable predictive criteria for distal caries of the second molar. To analyze the correlation of the distal caries of the second molar and the eruption state of the mandibular third molar using panoramic radiographs statistically and propose the acceptable guideline for preventive extraction of the mandibular third molar. 786 patients who were extracted the mandibular third molar from 2002 to 2006 at Samsung medical center were examined. The presence and absence of distal caries of mandibular second molar, age, gender, angulation, impaction degree, distance between distal cementoenamel junction of the second molar and mesial cementoenamel junction of the mandibular third molar were assessed. 79.6% of third molars had a mesial angulation of between 40 degrees and 80 degrees. The mean age of third molar removal for distal caries of second molar was 33.86+/-9.81. The prophylactic removal of a mesio-angular third molar about 40 degrees and 80 degrees could prevent distal cervical caries forming in the mandibular second molar.
Humans ; Molar ; Molar, Third ; Root Caries ; Tooth Cervix

The purpose of this study is to compare and to evaluate the effect of pH and lactic acid concentration on the progression of artificial root caries lesion using polarizing microscope, and to evaluate the morphological changes of hydroxyapatite crystals of the demineralized area and to investigate the process of demineralization using scanning electron microscope. Artificial root caries lesion was created by dividing specimens into 3 pH groups (pH 4.3, 5.0, 5.5), and each pH group was divided into 3 lactic acid concentration groups (25 mM, 50 mM, 100 mM). Each group was immersed in acid buffer solution for 5 days and examined. The results were as follows: 1. Under polarized microscope, the depth of lesion was more effected by the lactic acid concentration rather than the pH. 2. Under scanning electron microscope, dissolution of hydroxyapatite crystals were increased as the lactic acid concentration increased and the pH decreased. 3. Demineralized hydroxyapatite crystals showed peripheral dissolution and decreased size and number within cluster of hydroxyapatite crystals and widening of intercluster and intercrystal spaces as the pH decreased and the lactic acid concentration increased. 4. Under scanning electron microscope evaluation of the surface zone, clusters of hydroxyapatite crystals were dissolved, and dissolution and reattachment of crystals on the surface of collagen fibrils were observed as the lactic acid concentration increased. 5. Under scanning electron microscope, demineralization of dentin occurred not only independently but also with remineralization simultaneously. In conclusion, the study showed that pH and lactic acid concentration influenced the rate of progression of the lesion in artificial root caries. Demineralization process was progressed from the surface of the cluster of hydroxyapatite crystals and the morphology of hydroxyapatite crystals changed from round or elliptical shape into irregular shape as time elapsed.
Collagen ; Dentin ; Durapatite ; Hydrogen-Ion Concentration* ; Lactic Acid* ; Root Caries*

OBJECTIVETo survey the tooth decay of the first molars among the people in area of northeast China in order to provide the foundation for prevention and treatment strategies of caries.

METHODSAccording to the third national oral health investigation of epidemiology, the dental caries of first permanent molars were examined among 9394 people aged 5, 12, 35-44 and 65-74 in northeast China. The data were analyzed by SPSS 13.0 statistical software. Dental caries prevalence rate and DMFT (dmft) of first permanent molar were calculated.

RESULTSThe prevalence of crown and root dental caries in northeast China were 26.86% and 3.81% respectively, mean DMFT (dmft) of crown and root dental caries were 0.41 and 0.04 respectively. There were significant differences of dental caries among provinces in northeast China. Mandibular first molar suffered from dental caries easily. The prevalence of caries of female was higher than that of male (P<0.01), but there was not significant difference of prevalence of root caries between two sexes (P>0.05). Except Jilin province, there were significant differences of prevalence of crown caries between city and rural area in Liaoning and Heilongjiang provinces (P<0.01). It was no significant difference of prevalence and mean DMFT (dmft) of root caries between city and rural area in each province (P>0.05).

CONCLUSIONThe prevalence of dental caries of the first molar among the people in northeast China is high. The dental caries prevention and cure of first permanent molar should be emphasized in oral health field.

China ; Dental Caries ; Female ; Humans ; Male ; Molar ; Oral Health ; Prevalence ; Root Caries

OBJECTIVES: Crown-root fracture and cervical caries in maxillary premolars constitute a challenge in cases of subgingival placement of restoration margins. Surgical extrusion has been practiced successfully in permanent anterior teeth. The aim of the present retrospective study was to assess the clinical outcome of surgical extrusion after orthodontic extrusion in maxillary premolars. MATERIALS AND METHODS: Twenty-one single, tapered root maxillary premolars with subgingival crown-root fracture or caries were included. Presurgical orthodontic extrusion was performed on all teeth to prevent root resorption. Extent of extrusion and rotation was determined based on crown/root ratio. The postoperative splinting period was 7 to 14 days. Clinical and radiographic examination was performed at an interval of 1, 2, and 3 months. RESULTS: After the mean follow-up of 41.9±15.2 months, failure was observed as increased mobility in 3 of 21 cases. No significant difference was observed in the outcome of surgical extrusion based on tooth type, age, sex, 180° rotation, or time for extraction. Furthermore, marginal bone loss was not observed. CONCLUSION: Surgical extrusion of maxillary premolars can be a possible therapeutic option in cases of subgingival crown-root fracture.
Bicuspid ; Follow-Up Studies ; Orthodontic Extrusion ; Retrospective Studies ; Root Caries ; Root Resorption ; Splints ; Tooth

OBJECTIVETo discuss orthodontic extrusion of crown-root fractured teeth before restoration.

METHODS3 cases with fractured teeth and 2 cases with root caries were performed canal therapy.

RESULTSOrthodontic extrusion of the root was carried out before restoration. All cases were satisfactory after treatment.

CONCLUSIONSOrthodontic extrusion of remaining root before restoration not only can maintain the remaining root but also obtain functional and esthetic results.

Humans ; Root Canal Therapy ; Root Caries ; therapy ; Tooth Crown ; injuries ; Tooth Fractures ; therapy ; Tooth Movement Techniques ; methods ; Tooth Root ; injuries

OBJECTIVEActinomyces are members of the indigenous oral microbiota which have been implicated in root caries, but their role in childhood caries initiation and progression is not well-understood. The distribution of Actinomyces in supragingival plaque on the primary teeth and the relationship between oral Actinomyces spp. and childhood caries primarily were investigated.

METHODSForty children aged from three to five years old were divided into two groups. Twenty children were caries-free and twenty were caries-susceptible. Dental plaque samples from different places of the teeth were collected with sterile toothpick and polymerase chain reaction was performed with specific primers which were designed for this research.

RESULTSActinomyces spp. were detected 100% in the caries-free group, while 95% in the caries-susceptible group. There was no significant differences between the two groups (P > 0.05). Actinomyces naeslundii, Actinomyces odontolyticus, Actinomyces gerencseriae, Actinomyces israelii and Actinomyces viscosus all could be detected in both groups. The prevalence of Actinomyces naeslundii, Actinomyces gerencseriae and Actinomyces odontolyticus were higher in caries-free group than those in caries-susceptible group (P < 0.05), while the prevalence of Actinomyces israelii and Actinomyces viscosus had no significant difference between the two groups (P > 0.05).

CONCLUSIONActinomyces is the main colonized bacteria in the supragingival plaque of children. The prevalence of the Actinomyces spp. may have a negative relationship with the childhood caries, and has nothing to do with different places of the teeth.

Actinomyces ; Bacteria ; DNA, Bacterial ; Dental Caries ; Dental Plaque ; Humans ; Polymerase Chain Reaction ; Root Caries ; Tooth ; Tooth, Deciduous