Apical root resorption in maxillary incisors when employing micro-implant and J-hook headgear anchorage: a 4-month radiographic study / 华中科技大学学报（医学）（英德文版）

This study evaluated, over a 4-month study period, the amount of apical root resorption occurring in maxillary central incisors following their retraction when employing either micro-implant or J-hook headgear anchorage. The prospective randomised clinical trial was conducted in Orthodontic Clinic, College of Stomatology, China from 2008-2009. Subjects are patients requiring fixed appliances on waiting list (n=20). In female Han Chinese patients aged from 16-26 years, standardized periapical radiographs from 10 randomly assigned patients with maxillary protrusions comprising the micro-implant group, and from 10 similar patients comprising the J-hook headgear group, were assessed for maxillary central incisor apical root resorption. Measurements before and after orthodontic therapy were also obtained from lateral cephalometric radiographs to calculate incisor horizontal retraction and vertical intrusion distances. Estimated retraction force vectors were calculated in horizontal and vertical directions for both treatment groups. Data analysis employed t-tests and the Pearson correlation test, with α=0.05 for statistical significance. The results showed that when compared with the J-hook group, significantly more apical root resorption shortening of the maxillary central incisors was observed in the micro-implant group (1.27 mm difference, 95% CI=0.70-1.84, P<0.001), which was associated with a significantly larger retraction distance (P=0.004) and a smaller vertical force component (P<0.0001). We are led to conclude that continuous activation of the nickel-titanium coil springs used in the micro-implant group resulted in significantly more apical root resorption shortening and maxillary central incisor retraction than when intermittent J-hook retraction was employed. The employment of continuous duration orthodontic forces presents a risk for increased apical root resorption that requires careful radiographic monitoring.

Bilateral maxillary fused second and third molars: a rare occurrence / 国际口腔科学杂志·英文版

This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography (CBCT). A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the second molar. However, CBCT revealed that a third molar was fused to the second molar. Unexpectedly, the maxillary left third molar also was fused to the second molar, and the crown of an unerupted supernumerary fourth molar was possibly also fused to the apical root region of the second molar. Operative procedures should not be attempted without adequate radiographic investigation. CBCT allowed the precise location of the root canals of the right maxillary fused molar teeth to permit successful endodontic therapy, confirmed after 6 months.

Apical root resorption in maxillary incisors when employing micro-implant and J-hook headgear anchorage: a 4-month radiographic study / 华中科技大学学报（医学）（英德文版）

This study evaluated, over a 4-month study period, the amount of apical root resorption occurring in maxillary central incisors following their retraction when employing either micro-implant or J-hook headgear anchorage. The prospective randomised clinical trial was conducted in Orthodontic Clinic, College of Stomatology, China from 2008-2009. Subjects are patients requiring fixed appliances on waiting list (n=20). In female Han Chinese patients aged from 16-26 years, standardized periapical radiographs from 10 randomly assigned patients with maxillary protrusions comprising the micro-implant group, and from 10 similar patients comprising the J-hook headgear group, were assessed for maxillary central incisor apical root resorption. Measurements before and after orthodontic therapy were also obtained from lateral cephalometric radiographs to calculate incisor horizontal retraction and vertical intrusion distances. Estimated retraction force vectors were calculated in horizontal and vertical directions for both treatment groups. Data analysis employed t-tests and the Pearson correlation test, with α=0.05 for statistical significance. The results showed that when compared with the J-hook group, significantly more apical root resorption shortening of the maxillary central incisors was observed in the micro-implant group (1.27 mm difference, 95% CI=0.70-1.84, P<0.001), which was associated with a significantly larger retraction distance (P=0.004) and a smaller vertical force component (P<0.0001). We are led to conclude that continuous activation of the nickel-titanium coil springs used in the micro-implant group resulted in significantly more apical root resorption shortening and maxillary central incisor retraction than when intermittent J-hook retraction was employed. The employment of continuous duration orthodontic forces presents a risk for increased apical root resorption that requires careful radiographic monitoring.

Report and analysis of periodicals of oral science in China / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To review and analyze the history and current situation of stomatological journals in China from 1949 to 2009.</p><p><b>METHODS</b>The data from journal database, web sites and yearbooks were collected, and the information on Chinese dental journals, national economic indicators and the development in dental disciplines from 1949 to 2009 were obtained.</p><p><b>RESULTS</b>The dental journals numbered one kind, four issues in 1949 and 32 kinds, 204 issues in 2009. China's gross domestic product (GDP) was from 67.9 billion Yuan in 1949 to 30.067 trillion Yuan in 2008.</p><p><b>CONCLUSIONS</b>The quantity of stomatological journals in China has increased remarkably over the past 60 years.</p>

Clinical research methodology in dentistry

The objectives of this article are to assist dental professionals in obtaining information on evidence-based dentistry and to design focused clinical research projects. The importance of asking the right questions, of randomised controlled trials, of writing a detailed research proposal and of obtaining an early consultation with an experienced statistician are emphasized

Clinical and technical aspects of occlusal reconstruction in oral rehabilitation

Two basic occlusion schemes that can be used for the oral rehabilitation of patients following extensive tooth tissue loss are discussed. Irrespective of using a conformative or a reorganised occlusion approach, accurate and reproducible jaw registrations and the correct transfer of the occlusal records to the working casts for mounting on a semi-adjustable articulator are essential. In patients who require oral rehabilitation at a re-established occlusal vertical dimension, a multidisciplinary approach is often advisable. Adjunctive orthodontic treatment can facilitate the subsequent prosthodontic treatments and also allow a more minimally invasive approach to be considered, such as the use of adhesive retainers for fixed partial dentures. Conservation of sound tooth tissue by using dental implants can also optimise the functional and aesthetic results. Careful sequential occlusal reconstruction procedures are required for successful oral rehabilitation. This is a review article

Variables affecting dental health changes in long-term patients attending three selected private practices

OBJECTIVE: Very little information is available on the long-term effect of restorative treatments on dental health changes, and of the variables that might affect such changes. Therefore, the present study investigated the effects of six variables or factors on the long-term dental health of patients who received restorative treatments from private general practitioners. MATERIALS AND METHOD: The casenote records of 100 adult patients treated by 20 dentists in three selected city practices were examined, and the dental health at each course of restorative treatment was recorded using DMF and T-Health indices. The dental health of the patients deteriorated slowly over a mean of 24.8'8.7 [SD] years. Patient age, practice location, and the number of changes of dentist had very significant effects on the rates of change of the DMFT and the T-Health indices, P < 0.01. Deterioration rates were higher for younger patients and when patients were treated by only one dentist or, conversely, by more than 10 dentists. Gender difference, change of dentist, and frequency of patient attendance [< 1 year, > 1 year] had no significant effects. CONCLUSIONS: These mainly, regularly attending patients showed a slow deterioration in their long-term dental health. The rates of deterioration slowed with increasing age and when treatments were generally provided by relatively few dentists

Radiopacity of viscous glass ionomer cement and resin-ionomer restorative matrials

To investigate the radiopacities of newer viscous aesthetic glass ionomer cements [GICs] that may be used with the atraumatic restorative treatment [ART] approach, as compared with other conventional GICs, resin-modified GICs, compomers, and a resin composite. Radiographs were taken of specimens placed in Teflon moulds, together with an attached aluminium stepwedge. Assessments were made by comparison of the radiopacities of the specimens with those of the stepwedge, and then the radiographs were sorted by rank into groups with approximately the same radiopacities. The newer viscous GICs should provide satisfactory clinical radiopacities when placed in different cavity locations and sizes in posterior teeth. The radiopacities of two other GICs were unsatisfactory. Posterior restorative materials should have radiopacities equal to or slightly greater than similar thicknesses of enamel, and the material samples tested should approximate the size of smaller carious lesions that need to be restored. The ISO 4049 standard for the radiopacity of resin-based restorative materials should be reviewed

A clinical evaluation of filling radiation caries / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the clinical effects of filling for radiation carious cavities.</p><p><b>METHODS</b>146 carious cavities of 15 patients after radiotherapy for head and neck malignancies were included and were filled with two new GIC (Ketac-Molar and Fuji IX). The 2 years follow-up results were evaluated with USPHS evaluation criterion.</p><p><b>RESULTS</b>(1) The 2 years excellent rates were 51.7% in Ketac-Molar and 52.3% in Fuji IX, no significant differences. (2) Failures and defects were mainly occurred after 1 and 2 years. The main reason of failure was loss of filling. Marginal staining was a common shortcoming of the two materials. (3) There were no significant differences in main indexes except retention.</p><p><b>CONCLUSIONS</b>It is successful for radiation caries to be filled with Ketac-molar and Fuji IX, and is practically significant in stomatological clinic.</p>