Diagnosis of dentin involvement in occlusal caries based on visual and radiographic examination of the teeth

The purpose of the present study was to examine the validity of visual, radio-graphic and combined visual-radiographic examination of occlusal caries, with special reference to the diagnosis of dentin lesions, using the microscopic diagnosis after sectioning the teeth as validating criterion. Thirty extracted permanent molar teeth with signs of occlusal caries were selected and radiographed using a standard method similar to bitewing. Ten dentists, five from the Department of Cariology and Endodontics and five from the Department of Pedodontics, were asked to make a visual, radiographic and combined visual-radiographic caries examination with an interval of at least 1 month between different examinations. The teeth were sectioned bucco-lingually and the caries assessed as enamel or dentin lesion in a stereomicroscope. The sensitivity/specificity of the diagnoses of dentin lesions was 0.72/0.41 for the visual, 0.66/0.50 for the radiographic, and 0.86/0.64 for the combined visual-radiographic examinations. The Receiver Operating Characteristic (ROC) method revealed a statistically significant difference between combined visual-radiographic examination and the two other, but not between the isolated visual or radiographic examination. It is concluded that the combined use of visual and radiographic examination is belter than either visual or radiographic examination alone.     

同一个体乳牙列龋与恒牙列龋的相关性研究

目的：探讨同一个体乳牙龋与其年轻恒牙龋之间是否具有相关性，是否可以通过乳牙龋预见其恒牙龋的发生。方法：对293名5～6岁替牙期的儿童进行4年的跟踪调查，记录其在1999年和2003年时的乳、恒牙患龋情况，并进行统计学分析。结果：乳牙列龋与恒牙列龋之间相关性存在统计学意义。结论：乳牙列患龋严重的儿童，其恒牙患龋的可能性相对增高，可达乳牙列无龋者的4倍。特别是乳磨牙龋对其恒牙龋更具有预见价值。     

Diagnosis of dentin involvement in occlusal caries based on visual and radiographic examination of the teeth.

The purpose of the present study was to examine the validity of visual, radiographic and combined visual-radiographic examination of occlusal caries, with special reference to the diagnosis of dentin lesions, using the microscopic diagnosis after sectioning the teeth as validating criterion. Thirty extracted permanent molar teeth with signs of occlusal caries were selected and radiographed using a standard method similar to bitewing. Ten dentists, five from the Department of Cariology and Endodontics and five from the Department of Pedodontics, were asked to make a visual, radiographic and combined visual-radiographic caries examination with an interval of at least 1 month between different examinations. The teeth were sectioned bucco-lingually and the caries assessed as enamel or dentin lesion in a stereomicroscope. The sensitivity/specificity of the diagnoses of dentin lesions was 0.72/0.41 for the visual, 0.66/0.50 for the radiographic, and 0.86/0.64 for the combined visual-radiographic examinations. The Receiver Operating Characteristic (ROC) method revealed a statistically significant difference between combined visual-radiographic examination and the two other, but not between the isolated visual or radiographic examination. It is concluded that the combined use of visual and radiographic examination is better than either visual or radiographic examination alone.     

Age-related odontometric changes of human teeth

OBJECTIVE: The number of older patients requiring restorative treatment are likely to increase due to improvements in oral health and increased longevity. However, aging odontometric data are lacking. The aim of this study was to determine possible changes in pulp cell density, pulp area, and dentinal thickness with age. STUDY DESIGN: Incisors (50), canines (39), premolars (51), and molars (7) extracted from 60 patients aged between 10 and 59 years, were analyzed histomorphometrically for cell density (odontoblasts, subodontoblasts, and pulp core fibroblasts) and dentinal thickness. RESULTS: With increasing patient age, in both crown and root aspects of teeth, dentinal thickness increased (P <.001), while the density of odontoblasts (P <.001), subodontoblasts (P = 0.001), and pulp fibroblasts (crown, P <.011; root, P =.0015) decreased. The degree of age-related changes in teeth appeared to be asymmetrical, with decreases in the root being greater than in the crown. At all ages pulp cell densities, including odontoblasts, within the crown were greater than in the root (P <.001), even though the calculated rate of dentinal deposition was greatest in the root. CONCLUSION: Decreases in pulp cell density may reduce pulp repair activity after restorative treatments, although increases in dentinal thickness may aid pulp protection. An understanding of these age-related changes will influence the provision of restorative and endodontic care and benefit older patients.     

年轻恒牙患龋预测的前瞻性研究——龋病预防对恒牙龋病预测效果的影响

目的：研究龋病预防措施对恒牙龋病预测效果的影响。方法：通过测定73名5岁儿童的当前患龋情况（dmfs）、唾液变形链球菌计数、唾液缓冲能力，根据已制定的标准检测出龋高／低危儿童，再分组分别采取或不采取龋病预防措施进行观察。结果：3年、5年后2组儿童龋病预测可信度有显著性差异（P〈0．05），预防组比非预防组明显降低，3年后2组分别为56％、74％，5年后分别为53％、69％。结论：有效的口腔预防措施可降低未来龋病的发生，也可影响对未来龋病的预测。     

Neuromuscular objectives of the human masticatory apparatus during static biting

OBJECTIVE: The central nervous system controls the muscles of mastication and may dictate muscle outputs according to a biologically important objective. This study tested the hypotheses that (a) the effective sagittal TMJ eminence morphology, and (b) the outputs of the masticatory muscles during static biting, are consistent with minimisation of joint loads or minimisation of muscle effort. DESIGN: Numerical modelling predicted effective eminence morphology (from sagittal plane directions of TMJ force for centred loading over a range from molar to incisor biting) and TMJ and muscle forces during static unilateral biting in seven subjects. In vivo effective eminence morphology was measured from jaw tracking recorded from each subject. Muscle activities during biting tasks on first molar and incisor teeth were measured by electromyography using surface or indwelling electrodes. RESULTS: Subject-specific predicted effective eminence morphology correlated with in vivo data (0.85< or =R2< or =0.99). Mixed and random coefficient analysis of covariance indicated good agreement between predicted and measured muscle outputs for all muscles of mastication investigated. Individual linear regression analysis showed that modelled muscle outputs accurately predicted EMG data, with average errors of 8% for molar and 15% for incisor biting. CONCLUSIONS: Effective sagittal eminence morphology was consistent with minimisation of joint loads for all subjects. Masticatory muscle outputs during unilateral biting were consistent with minimisation of joint loads or minimisation of muscle effort, or both, depending on the subject. These results are believed to be the first to test model predictions of muscle output during biting for all muscles of mastication.