Clinical, histological and microbiological study of hand-excavated carious dentine in extracted permanent teeth.

Changes in cultivable flora in dentine samples collected before and after hand excavation were examined in association with clinical status of the cavity surface, light microscopy and scanning electron microscopy (SEM). Thirty-five extracted permanent molar teeth with an occlusal caries lesion were excavated with hand instruments according to the atraumatic restorative treatment (ART) approach. Excavation pressure, dentine colour and consistency were recorded at the dentine-enamel junction (DEJ) prior to carious dentine removal and at the cavity floor after the final excavation; a microbiological sample of dentine was taken at both stages. Twelve restored teeth; six with positive and six with negative bacterial growth on the second sample, were selected for light microscopy and SEM. The hand-excavation removed tooth structure was soft, irreversibly damaged, dark and highly infected. Hand excavation reached dentine of increased hardness with a more normal colour to provide a sound structural base for restoration. Light and SEM examination of the cavity floor showed infected dentinal tubules in all 12 teeth examined. Linear logistic analysis showed a statistical association between light-yellow dentine on the cavity floor and an absence of bacterial growth (P = 0.006). This short-term in vitro study showed that caries-producing bacteria remained in dentine close to the cavity floor in 26/35 teeth despite clinical observations that indicated a suitably prepared cavity floor.     

Histological validation of ICDAS II and radiological assessment of occlusal carious lesions in permanent teeth

The International Caries Detection and Assessment System (ICDAS) was introduced for a detailed evaluation of dental caries. The aim of the present study was to compare the ICDAS scores and radiologically evaluated caries depths to the histologically evaluated carious lesions in permanent teeth. 84 freshly extracted human teeth were included. Visual examination and scoring of the occlusal aspect were performed according to the ICDAS II criteria after completing a respective e-learning programme to support training in the use of ICDAS. Bucco-lingual digital X-ray images of the teeth were taken. Specimens were then fixed in formalin and embedded in a photocuring one-component methacrylate-based resin. Longitudinal sections were cut and stained with rhodamine B, fuchsin and acetic light green dye to assess the caries extension by light microscopic analysis. Assessing ICDAS II scores and histological findings, a rank correlation coefficient of r = 0.890 could be found. ICDAS II/radiology and histology/radiology showed correlation coefficients of r = 0.658 and 0.661, respectively. Evaluating receiver operating characteristic (ROC) curves, no exact predictability could be found for caries lesions in enamel for both ICDAS II and radiological evaluation. Focussing on deep dentin lesions, values of 0.940 (ICDAS II) and 0.845 (radiology) showed high predictability with respect to the histologically observed caries extension. The present study indicates an acceptable validity of the ICDAS II criteria when applied to permanent teeth. Especially, dentin lesions can be reliably detected. Thus, ICDAS assessment provides the possibility of reducing X-ray exposure for caries detection.     

乳磨牙龋病和恒牙萌出与生长发育的相关性研究

目的了解广州市白云区城乡结合部7~8岁儿童乳磨牙龋病和恒牙萌出情况并探讨其与生长发育的关系,为合理开展乳牙龋病防治提供理论依据。方法采用横断面研究方法,随机抽取广州市白云区城乡结合部11所小学7~8岁儿童1 543名作为研究对象,进行口腔检查,记录乳磨牙龋病和恒牙萌出情况,测量身高体重,并计算体质量指数(Body Mass Index,BMI)(kg/m2),按国际肥胖委员会(IOTF)标准分为消瘦、正常、超重和肥胖四组。以Logistic回归分析是否超重/肥胖与患龋和恒牙萌出的相关性。结果调查的7~8岁儿童,乳磨牙患龋率为80.0%,龋均为3.45±2.72,恒牙萌出均数为10.57±2.12。随体质量指数升高,乳磨牙龋齿数量降低,恒牙萌出数增高。结论乳磨牙龋病和恒牙萌出与生长发育关系密切。     

氟保护漆Duraphat治疗前牙初期龋损的临床效果

目的 探讨氟保护漆Duraphat对前牙初期龋损白垩色斑块的治疗效果。方法 共纳入并分析120例患者146个前牙唇侧白垩斑病损,分为三组：A组（涂氟保护漆Duraphat＋口腔健康教育组,n = 52）,B组（口腔健康教育组,n = 47）和C组（对照组,n = 47）。由同一位已经过培训的医生采用牙周探针对白垩斑的直径及龋活动性进行评估,同时对研究对象的口腔卫生采用改良菌斑指数进行评估。结果 A组在接受2年的涂氟治疗后其白垩斑直径明显缩小,与另外两组差异有统计学意义（X^2=29.1,P 〈 0.001）,初期龋损白垩色斑块活动性龋的比例明显下降（χ^2=42.5,P 〈 0.001）。结论 氟保护漆Duraphat能有效治疗光滑面的初期龋损。     

Unilateral primary or secondary retention of permanent teeth,and dental malformations

The purpose of the present investigation was to describe the dentition in subjects with local primary or secondary unilateral retention of two or more permanent teeth, and to elucidate the aetiology by comparing the regions of retention with the innervation pattern of the jaws. The material comprised radiographic dental orthopantomograms (OTP) from 12 patients with an age range of 6-18 years (six females and six males). The locations of retention and the dental morphology in the affected regions were analysed. Comparison with contralateral teeth was undertaken and the innervation pattern of the affected field was considered. Varying degrees of dental root malformation were found to be associated with primary and secondary retention. More pronounced root malformations were observed in subjects with several affected teeth. A connection between unilateral retained permanent teeth and temporary or permanent disruption of the nerve supply to the affected region is suggested.     

The restoration of permanent immature anterior teeth,root filled using MTA: A review

Objectives

Immature anterior teeth are at high risk of root fracture following root canal treatment. The literature was explored to determine the current status for post-endodontic restorative management of these teeth.

Data and sources

The authors explored multiple search engine databases to November 2008. Experiments included in the review involved simulated human or animal immature teeth with mineral trioxide aggregate as an apical plug. The experiments were designed to assess and compare the fracture strength of teeth restored with various materials. Studies that did not fulfil inclusion criteria were omitted from the review.

Study selection

Four in vitro studies fulfilled selection criteria and were systematically reviewed. All studies differed in sources of teeth, their simulated immature tooth model and mode of force application.

Clinical Implications

Current evidence, mostly from laboratory studies, suggests the use of composite resin materials placed deep into the coronal aspect of the root canal to impart superior fracture resistance. Further clinical research is needed to assess other reinforcing materials, which include a variety of post systems and luting agents.     

Disinfection/sterilization of extracted teeth for dental student use

Extracted human teeth are used in many preclinical courses. While there has been no report of disease transmission with extracted teeth, sterilization of teeth used in the teaching laboratory should be a concern. The purpose of this study was to determine the effectiveness of different sterilization/disinfection methods of extracted human teeth using Bacillus stearothermophilus, a bacteria resistant to heat and frequently used to test sterilizers. In this study, 110 extracted molars with no carious lesions were collected and stored in buffered saline. An endodontic occlusal access preparation was cut into the pulp chamber of each tooth. Pulp tissue in the chamber was removed with a broach. Approximately 1 x 10(5) B. stearothermophilus endospores in culture medium were injected into the pulp chamber, sealed with Cavit G, and then placed in sterile saline for twelve hours. Ten teeth were placed into each of eleven groups. Seven groups were immersed for one week in one of the following solutions: a) sterile saline (control group), b) 5.25% NaOCl, c) 2.6% NaOCl, d) 1% NaOCl, e) 10% buffered formalin, f) 2% gluteraldehyde, g) 0.28% quaternary ammonium. Four additional groups were treated by h) 10% formalin for two days, i) 10% formalin for four days, j) autoclaving at 240 degrees F and 20 psi for twenty minutes, and k) autoclaving at 240 degrees F and twenty psi for forty minutes. Each tooth was then aseptically split and placed in an individual test tube with growth medium. Samples were examined for evidence of growth (turbidity) at forty-eight hours. Only autoclaving for forty minutes at 240 degrees F and 20 psi or soaking in 10 percent formalin for one week were 100 percent effective in preventing growth. A chi-square analysis of the data indicates these two methods were significantly better than all other methods (p<0.001).     

Fracture resistance of simulated immature teeth filled with resilon, gutta-percha, or composite

The purpose of this study was to evaluate the fracture resistance gained by filling root canals of simulated immature teeth with either Resilon, gutta-percha, a self-curing flowable composite resin (BisFil 2B), or a self-curing hybrid composite resin (BisFil II). Seventy-two sheep incisors were divided into six groups of 12 teeth each. Negative controls received no treatment. Teeth in all other groups were prepared until a size 120 LightSpeed LSX instrument could be passed out the apex. After apical placement of a mineral trioxide aggregate (MTA) barrier, the canals were filled with their respective test material to the facial CEJ. The positive control canals were left unfilled. The access openings (including positive controls) were restored with BisFil II. Each root was horizontally fractured through the test material using an Instron. The mean peak loads to fracture were recorded. The hybrid composite resin (BisFil II) was the only material significantly more fracture resistant than positive controls (p < 0.017).     

Clinical and radiographic appearance of proximal carious lesions at the time of operative treatment in young permanent teeth

Clinical tissue changes were recorded during restorative treatment of proximal carious lesions of young premolars and molars. 60 proximal surfaces with radiolucencies in the inner half of the enamel or the outer half of the dentin were treated. The extent and character of the tissue changes were documented with photographs taken during drilling and evaluated after magnification. The maximum extent for each lesion was correlated to the extent of the radiographically observed lesion. The results showed that 70% of the restored surfaces were associated with a breakdown of the enamel surface. When the radiolucency did not extend deeper than into the inner half of the enamel, cavities were found in 61%; for lesions with a radiolucency extending into the outer half of the dentin the percentage was 78%. In the majority of cases the cavity was limited to the enamel. In all cases discoloration was observed in the enamel. The dentin was soft and discolored in 83%. Severe damage of tooth substance was found in 12% of the teeth.     

Clinical and radiographic appearance of proximal carious lesions at the time of operative treatment in young permanent teeth

Clinical tissue changes were recorded during restorative treatment of proximal carious lesions of young premolars and molars. 60 proximal surfaces with radiolucencies in the inner half of the enamel or the outer half of the dentin were treated. The extent and character of the tissue changes were documented with photographs taken during drilling and evaluated after magnification. The maximum extent for each lesion was correlated to the extent of the radiographically observed lesion. The results showed that 70% of the restored surfaces were associated with a breakdown of the enamel surface. When the radiolucency did not extend deeper than into the inner half of the enamel, cavities were found in 61%; for lesions with a radiolucency extending into the outer half of the dentin the percentage was 78%. In the majority of cases the cavity was limited to the enamel. In all cases discoloration was observed in the enamel. The dentin was soft and discolored in 83%. Severe damage of tooth substance was found in 12% of the teeth.     

Partial pulpotomy for immature permanent teeth, its present and future

Traumatic or carious exposure of a vital pulp in an immature permanent tooth presents a significant clinical challenge to maintain proper vitality. Currently available procedures include direct pulp capping, complete pulpotomy and partial pulpotomy. This paper reviews the application of partial pulpotomy in immature permanent teeth and provides prognostic and technique guidance.     

龋齿、牙周炎患牙和健康牙的菌斑生物膜特征

目的研究牙面菌斑生物膜特征与口腔疾病的关系。方法选择牙周健康而牙冠严重龋坏的龋齿5颗、无龋损而极度松动的牙周炎患牙6颗及正畸原因拔除的健康牙4颗,在扫描电镜下,观察分析龈上、龈下及移行生态区的菌斑生物膜特征。结果龋齿、牙周炎患牙和健康牙的牙面均观察到细菌混合物组成的菌斑生物膜,健康牙菌斑生物膜以球菌为主,放线菌和短杆菌少量;龋齿牙的龋坏处为坏死组织和细菌,龋边缘及龈沟处的球菌和短杆菌较健康牙多;牙周炎患者牙菌斑生物膜的细菌种类多,在龈上、龈下移行处可见典型的玉米棒状菌斑或以杆菌为主的紧密附着菌斑,龈下可见球菌、杆菌、梭菌及螺旋体等构成的复杂菌斑。结论龋齿、牙周炎患牙和健康牙菌斑生物膜细菌组成、集聚秩序和立体结构不同,菌斑生物膜的形成与细菌的附着、集聚、生长有关,也与局部病变密切相关。     

Timing of first restorations in permanent teeth: a new system for oral health determination

Objectives: A system of oral health determination in which times between eruption of teeth and first restorations because of caries is measured is applied in a retrospective analysis of oral health data relating to rural health centres in Finland.

Method: The retrospective analysis was carried out using data relating to three health centres in different parts of Finland. The times between eruption and the placement of the first restorations in subjects up to 18 years of age were investigated.

Results: Between 10% and 25% of all permanent molar teeth were filled in the year of tooth emergence —the ‘immediate posteruptive step’. A steadily increasing restoration placement rate—the ‘ascending growth phase’—was observed after the ‘posteruptive step’. The restoration rate was found to plateau 5–8 years after eruption—the ‘retardation phase’.

Conclusions: Restoration increment curves with longitudinal measurements are believed to be a sensitive indication of oral health at both individual and population levels.     

Diagnosis and management planning for root‐filled teeth with persisting or new apical pathosis

Teeth may require further management following root canal treatment because of persisting or new apical pathosis. Management must be based on the diagnosis of the presenting condition and the history of the previous treatment, particularly in relation to when it was completed. Most root‐filled teeth with periapical pathosis should be re‐treated in the first instance via a conventional orthograde approach since most disease is related to an infected root canal system. However, this approach to treatment should only be followed if the tooth is suitable for further restoration and when the restoration has a good long‐term prognosis. Assessment of whether a tooth is suitable for treatment may not be possible until after restorations, caries, and cracks have been removed so that the remaining tooth structure can be visualized and assessed. Periapical surgery should be reserved for teeth with persistent symptoms and/or apical radiolucency following root canal re‐treatment and where the differential diagnosis suggests an ongoing periapical condition such as a true cyst, extra‐radicular infection, or foreign body reaction which cannot be addressed via an orthograde approach. If a tooth has to be extracted, it can be replaced with one of several forms of prostheses; implant‐supported prostheses are gaining popularity and have a proven track record, especially for single tooth replacements. The use of implants should be restricted to cases where teeth are already missing or where a tooth cannot be retained because it is not suitable for further restoration due to insufficient tooth structure.     

Remineralization of carious dentin. II: In vivo microradiographic and chemical studies in human permanent teeth capped with calcium hydroxide

The main aim of this in vivo study was to evaluate a possible remineralization of human carious dentin by means of chemical and microradiographic studies. Eighty-six samples of carious dentin were removed from 36 permanent teeth of 24 patients. These were divided into untreated (control) and chemically pure calcium hydroxide-capped (experimental) samples and analyzed at intervals varying from 10 to 120 days. They were classified according to depth of caries and degree of dentin softening and evaluated in relation to weight, phosphorus concentration, qualitative and quantitative microradiography and absolute values of total mineral content. One of two halves of each sample was selected for chemical studies and the other for total content of mineral salts. Experimental samples were examined with a light microscope and the results obtained showed a qualitative increase in radiopacity. Quantitatively, it was observed that, in the case of samples analyzed for phosphorus concentration, the average mean of differences in percentage increase after treatment was 9.6%, while for the samples evaluated microradiographically for total mineral content, it was 22.29%. In both cases, the differences were statistically significant.     

Evaluation of a new caries detecting dye for primary and permanent carious dentin

OBJECTIVE: This study evaluated the clinical efficacy of a new caries detecting dye using a laser fluorescence device (DIAGNOdent). METHOD: Primary and permanent teeth with dentin caries were stained with Caries Check (CC), containing 1% acid red in polypropylene glycol (MW=300) or Caries Detector (CD), containing 1% acid red in propylene glycol (MW=76). Primary-CC, primary-CD, permanent-CC and permanent-CD groups were prepared. In the CC groups, stained dentin was completely removed. In the CD groups, pink-stained dentin was retained according to the manufacturers' instructions. Cavities before and after caries removal were measured with the DIAGNOdent. Data were analyzed using ANOVA and Fisher's PLSD multiple comparison test at alpha=0.05. Regression analyses were performed between DIAGNOdent readings and scores obtained from the clinical parameters. RESULTS: For all groups, there were no significant differences in the DIAGNOdent readings before treatment. The DIAGNOdent readings after caries removal were: primary-CC (16.0+/-17.6), primary-CD (9.6+/-5.2), permanent-CC (11.0+/-7.0) and permanent-CD (7.1+/-3.8). Significant differences were identified between the permanent-CC and primary-CD, and permanent-CC and permanent-CD subgroups but not for the primary subgroups. Correlation coefficients between DIAGNOdent readings and clinical parameters were low. CONCLUSIONS: When dentin stained with Caries Check was completely removed, the DIAGNOdent readings were higher than those recorded when palely-stained pink dentin was retained with the Caries Detector, with significant difference observed for the permanent teeth. Caries Check may be used clinically to avoid excessive removal of caries-affected or sound dentin in permanent teeth but not in primary teeth.