Dentin matrix metalloproteinases (MMPs) are a family of host‐derived proteolytic enzymes trapped within mineralized dentin matrix, which have the ability to hydrolyze the organic matrix of demineralized dentin. After bonding with resins to dentin there are usually some exposed collagen fibrils at the bottom of the hybrid layer owing to imperfect resin impregnation of the demineralized dentin matrix. Exposed collagen fibrils might be affected by MMPs inducing hydrolytic degradation, which might result in reduced bond strength.
Most MMPs are synthesized and released from odontoblasts in the form of proenzymes, requiring activation to degrade extracellular matrix components. Unfortunately, they can be activated by modern self‐etch and etch‐and‐rinse adhesives. The aim of this review is to summarize the current knowledge of the role of dentinal host‐derived MMPs in dentin matrix degradation. We also discuss various available MMP inhibitors, especially chlorhexidine, and suggest that they could provide a potential pathway for inhibiting collagen degradation in bonding interfaces thereby increasing dentin bonding durability.
This review highlights the recent advances in X‐ray microcomputed tomography (Micro‐CT) applied in dental research. It summarizes Micro‐CT applications in measurement of enamel thickness, root canal morphology, evaluation of root canal preparation, craniofacial skeletal structure, micro finite element modeling, dental tissue engineering, mineral density of dental hard tissues and about dental implants. Details of studies in each of these areas are highlighted along with the advantages of Micro‐CT, and finally a summary of the future applications of Micro‐CT in dental research is given.
Cluster analysis was conducted on data from 5,169 United States (U.S.) Arizona children, age's 5‐59‐months with the goal of delineating patterns of caries in the primary dentition of pre‐school children without a priori pattern definitions.
Cluster analyses were conducted using all data for children ages 0–4 years in aggregate: 1) for all subjects, and 2) for subjects without crowned restored teeth. Each of these two sets of analyses consisted of 8 differently specified cluster analyses as a validation procedure.
The caries patterns identified from the clustering analysis are: 1) smooth surfaces (other than the maxillary incisor), 2) maxillary incisor, 3) occlusal surfaces of first molars, and 4) pit and fissure surfaces of second molars.
The cluster analysis findings were consistent with results produced by multidimensional scaling. These cross‐validated patterns may represent resulting disease conditions from different risks or the timing of various risk factor exposures. As such, the patterns may be useful case definitions for caries risk factor investigations in children under 60 months of age.
To find the relationship of periodontal status and dental caries status with oral health knowledge, attitude, behavior, among professional students in India.
In a cross sectional study, a total of 825 students (males: 577, females: 248) from six professions were surveyed using a self administered structured questionnaire including 41 multiple choice questions and the WHO Oral Health Assessment Form (1997). The data was analyzed using the SPSS version 13.0 to perform the Student's t‐test, ANOVA test, Scheffe's test and Chi‐square test, linear regression analysis.
The mean percentage scores of the students for knowledge were 53.25 ± 15.05; for attitude 74.97 ±20.48; and for behavior 59.09 ± 18.77. The percentage of students with calculus score was found to be significantly high (43.8%). The percentage of professional students with DMFT>4 was 14.1% and the percentage of students with decayed teeth was 46.2%. The regression analysis showed that the oral health behavior of the students was dependent on the attitude (P <0.001), but showed no significant linear relation with the knowledge. Also, that the mean DMFT score was dependent on the oral health behavior (P <0.05), but showed no significant relationship with the knowledge and attitude of the students. The periodontal status was independent on the knowledge, but showed a significant relationship with attitude and behavior of the students.
A positive attitude and adherence to good oral hygiene behaviors is associated with better oral health.
To determine cephalometrically the mechanism of the treatment effects of non‐extraction and multiloop edgewise archwire (MEAW) technique on postpeak Class II Division 1 patients.
In this retrospective study, 16 postpeak Class II Division 1 patients successfully corrected using a non‐extraction and MEAW technique were cephalometrically evaluated and compared with 16 matched control subjects treated using an extraction technique. Using CorelDRAW® software, standardized digital cephalograms pre‐ and post‐active treatments were traced and a reference grid was set up. The superimpositions were based on the cranial base, the mandibular and the maxilla regions,and skeletal and dental changes were measured. Changes following treatment were evaluated using the paired‐sample t‐test. Student's t‐test for unpaired samples was used to assess the differences in changes between the MEAW and the extraction control groups.
The correction of the molar relationships comprised 54% skeletal change (mainly the advancement of the mandible) and 46% dental change. Correction of the anterior teeth relationships comprised 30% skeletal change and 70% dental change.
The MEAW technique can produce the desired vertical and sagittal movement of the tooth segment and then effectively stimulate mandibular advancement by utilizing the residual growth potential of the condyle.
To investigate the relationship between the positioning of the lower central incisor and physical morphology of the surrounding alveolar bone.
Thirty‐eight patients (18 males, 20 females), with mean age of 13.4 years, were included in this study. As part of orthodontic treatment planning the patients were required to take dental Cone‐beam CT (CBCT) covering the region of lower incisors, the surrounding alveolar bone and the mandibular symphysis. The cephalometric parameters were designed and measured to indicate the inclination of lower central incisor and physical morphology of the adjacent alveolar bone. Computer‐aided descriptive statistical analysis was performed using SPSS 15.0 software package for Windows. A correlation analysis and a linear regression analysis between the incisor inclination and the alveolar bone morphology were performed.
Significant positive correlations were found between the lower central incisor inclination and the morphological contour of the alveolar bone (P <0.05). The lower central incisor root apex was closer to the lingual alveolar crest when it was buccally inclined.
The morphology of the alveolar bone may be affected by incisal inclination.
This paper reported a case of fusion between an impacted third molar and a supernumerary tooth, in which a surgical intervention was carried out, with the objective of removing the dental elements. The panoramic radiography was complemented by the Donovan's radiographic technique; but because of the proximity of the dental element to the mandibular ramus, it was not possible to have a final fusion diagnosis. Hence, the Cone‐Beam Computed Tomography—which provides precise three‐dimensional information—was used to determinate the fusion diagnosis and also to help in the surgical planning. In this case report we observed that the periapical, occlusal and panoramic were not able to show details which could only be examined through the cone‐beam computed tomography.