Je-Kang Du

Effects of denture maintenance on satisfaction levels of Taiwanese elderly using removable partial dentures: a pilot study

OBJECTIVE The aim of this study was to evaluate the correlation between patient satisfaction with removable partial dentures and denture maintenance by patients, including regular application of denture adhesives and cleansers. BACKGROUND The success of removable partial dentures depends on patient satisfaction with dentures and their regular denture maintenance. MATERIALS AND METHODS Demographic information, the Oral Impacts on Daily Performance (OIDP) indicator and details of denture maintenance (including the use of denture cleansers and adhesives) were collected from 193 (41.5% men and 58.5% women) participants by using questionnaires. A dentist performed oral examinations to evaluate denture function according to the OIDP items photographically and recorded the number of remaining teeth and Kennedys classification. RESULTS Most participants were satisfied with their removable partial dentures and tended to have higher satisfaction levels than the dentists estimation. Further, those using denture adhesives and cleansers had higher satisfaction levels than those not using such denture maintenance. CONCLUSIONS Appropriate education regarding denture use is important because regular denture maintenance by patients affects their degree of satisfaction with dentures, as well as the dentists skill and the patients oral condition. Dentists could use this information to predict the potential success of dentures.

Horizontal pull-out strength of orthodontic infrazygomatic mini-implant: an in vitro study.

Purpose:New modified mini-implants have recently come into use for reinforcing skeletal anchorage in orthodontic application. The aim of this study was to investigate the influence of the design of a mini-implant on its mechanical strength. Materials and Methods:We measured the insertion torques and horizontal pull-out strengths of 3 brands of infrazygomatic mini-implants (AbsoAnchor, Bioray, and Lomas; 2 mm for all). Five implants of each brand were manually driven 6 mm into the artificial bone. Significant differences in various parameters among the brands were investigated with the Kruskal–Wallis test. Results:There was no significant relationship between insertion torque and horizontal pull-out strength. The Bioray mini-implants had significantly greater horizontal pull-out strength than the AbsoAnchor mini-implants. Conclusions:The design of the mini-implant can influence its insertion torque and horizontal pull-out strength. In our findings, the horizontal pull-out strength of all mini-implants placed in the infrazygomatic crest was significantly greater than the orthodontic force applied.

Emergence Angles of the Cementoenamel Junction in Natural Maxillary Anterior Teeth

STATEMENT OF THE PROBLEM   Fabrication of normal crown contour to maintain gingival health is difficult in the absence of emergence angle data. PURPOSE   The aim of this study was to measure the geometric values of the emergence angles on the cementoenamel junction (CEJ) for natural maxillary anterior teeth. MATERIAL AND METHODS   This study collected 148 natural permanent maxillary anterior teeth (74 central incisors, 59 lateral incisors, and 15 canines) with intact cervixes for this study. The teeth were scanned with a three-dimensional (3D) scanner to construct 3D models. This study measured the emergence angles of the cervical CEJ on the zenith of labial, palatal, mesial, and distal, for each tooth. RESULTS   Measurements made on 148 maxillary anterior teeth showed the emergence angle to be within a narrow range from 11.30° to 15.26°, irrespective of the tooth location. There were no statistically significant differences between any two groups (p > 0.05). CONCLUSIONS   On the basis of measurements taken from natural teeth, we conclude that the emergence angles of the CEJ in natural maxillary anterior teeth should be 15° from the root surface. CLINICAL SIGNIFICANCE The information presented in this article may be useful in helping to create dental restorations with optional emergence angles over the CEJ in natural maxillary anterior teeth. Prior to the treatment the dentist should consider not only the fit of the crown, but also the emergence angles and contours of the soft tissues surrounding the involved teeth.

Reconstruction of the Soft Palate In Oral Cancer to Repair an Operative Defect with Speech Aid Prosthesis: A Case Report

A soft palate defect may result from surgical resection, and its consequences could include hypernasal speech and nasal regurgitation of food and liquids. A speech aid prosthesis fabricated for patients can improve nasal emission during speech, and assist in preventing nasal regurgitation of food. This article presents a case of the reconstruction of a soft palate defect by prosthetic obturation.

Biomechanical Analysis of Distal Extension Removable Partial Dentures with Different Retainers

The purposes of this study were to compare various retainer designs with different design philosophies based on stress breakers and rigid support. The technique of quasi-3-dimensional photoelastic stress analysis was used for this investigation. A photoelastic model was made with individual simulative materials for tooth structure and alveolar bone. The model was fabricated to simulate a mandibular Kennedy class Ⅱ modification 1 edentulous state with the right 1st premolar as the terminal abutment Six types of retainers were fabricated for the analysis: a wrought wire clasp; rest, proximal plate, Ⅰ-bar (RPI) system; conical crown telescopic retainer; rest, bi-proximal plate, Ⅰ-bar (RPPI) system; ring clasp, and cast circumferential clasp. For each experimental removable partial denture (RPD), a micro-load cell transducer was placed under the denture base to measure the denture base shearing load of the occlusal force. After 18 kg was loaded vertically on the occlusal table of the RPD, photoelastic stress distribution isochromatics and the denture base shearing load were obtained. Results indicated that an unfavorable stress gradient was found with the wrought wire clasp design, with the maximum stress (5.59 kg) being concentrated at the residual ridge while the minimum stress occurred at the abutment. A favorable stress gradient was found with the conical crown telescopic retainer design, with the stress (1.05 kg) being concentrated at the residual ridge. Within the limitations of this experiment, different retainer designs had different effects on the abutment and residual ridge. The retainers designed based on a rigid support philosophy concentrated more stress at the abutment and generated less stress at the residual ridge than those retainers designed with a flexible support.

The Difference Between Two Oral Appliances in Treating Obstructive Sleep Apnea: A Case Report

Oral appliances are a range of devices that are designed to alter upper airway patency. The efficiency of these appliances for treatment of obstructive sleep apnea (OSA) has been rarely discussed. This case report describes two designs of mandibular repositioning appliances used to treat OSA. A 36-year-old man was diagnosed with mild OSA by his physician. A single-piece, soft oral appliance and a two-piece, acrylic appliance were used in this patient. Polysomnography was performed three times (baseline, and with the single-piece, and two-piece appliances). The apnea/hypopnea index was improved significantly with both appliances, but to a greater degree with the single-piece soft appliance. Our study concluded that oral appliances may assist in the management of OSA.

Connecting Rigidities of Various Precision Attachments Compared with the Conical Crown Retained Telescope

The purpose of this investigation was to observe the connecting rigidity of various precision attachments and to compare their connecting rigidities with the conical crown retained telescope (CCT). The connecting rigidity of a retainer was assessed using the flexibility test to measure the mesial and distal end displacements. Four precision attachments were analyzed: the dovetail slide attachment beyeler, cylindrical slide attachment, Spang Stabilex and Mini SG. The CCT was used as the control. Although there were many statistically significant differences between the displacements with the various attachments, displacements when vertically loaded were very small: all mesial end displacements were within 3 μm and distal end displacements were 21.4 μm. The largest of the mesial end displacements when horizontally loaded was as large as 44.5 μm (dovetail slide beyeler), while the others were all below 16.5 μm. The same phenomena occurred with the distal end displacements when horizontally loaded: the largest was seen with the dovetail slide beyeler, followed sequentially by the Spang Stabilex, CCT, cylindrical slide, and the Mini SG. The distal displacement with the dovetail slide beyeler was as large as 75.2 μm; those with the others were all below 31.2 μm, with numerous statistically significant differences between the displacements with the various attachments. Thus, connecting rigidities of rigid precision attachments are very similar to CCT, and only the dovetail slide beyeler attachment is too weak to resist horizontal displacement force.

Insertion torque, resonance frequency, and removal torque analysis of microimplants

This study aimed to compare the insertion torque (IT), resonance frequency (RF), and removal torque (RT) among three microimplant brands. Thirty microimplants of the three brands were used as follows: Type A (titanium alloy, 1.5‐mm × 8‐mm), Type B (stainless steel, 1.5‐mm × 8‐mm), and Type C (titanium alloy, 1.5‐mm × 9‐mm). A synthetic bone with a 2‐mm cortical bone and bone marrow was used. Each microimplant was inserted into the synthetic bone, without predrilling, to a 7 mm depth. The IT, RF, and RT were measured in both vertical and horizontal directions. One‐way analysis of variance and Spearmans rank correlation coefficient tests were used for intergroup and intragroup comparisons, respectively. In the vertical test, the ITs of Type C (7.8 Ncm) and Type B (7.5 Ncm) were significantly higher than that of Type A (4.4 Ncm). The RFs of Type C (11.5 kHz) and Type A (10.2 kHz) were significantly higher than that of Type B (7.5 kHz). Type C (7.4 Ncm) and Type B (7.3 Ncm) had significantly higher RTs than did Type A (4.1 Ncm). In the horizontal test, both the ITs and RTs were significantly higher for Type C, compared with Type A. No significant differences were found among the groups, and the study hypothesis was accepted. Type A had the lowest inner/outer diameter ratio and widest apical facing angle, engendering the lowest IT and highest RF values. However, no significant correlations in the IT, RF, and RT were observed among the three groups.

Arsenic Trioxide-Induced Mandibular Osteomyelitis

Previously, arsenic was a popular devitalizing agent used to necrotize inflamed dental pulp to lower the pulp sensitivity owing to the unavailability of appropriate anesthesia. However, leakage from the apical foramen, lateral or accessory canals, or cracks in the tooth is common. This can be dangerous because of the reportedly high toxic effects of arsenic in both hard and soft tissues, leading to gingival and osseous necrosis and, consequently, osteomyelitis. Therefore, arsenic can prove fatal for both bones and teeth and is no longer used. We encountered a case involving a 50-year-old man who had developed mandibular osteomyelitis with lower lip paresthesia caused by arsenic trioxide used during endodontic treatment. The patient was treated with appropriate antibiotics, adjunctive hyperbaric oxygen therapy, and adequate surgical debridement. Hyperbaric oxygen therapy can induce neovascularization in necrosed tissues and improve bone and soft tissue healing. At a 4-year follow-up visit, bone healing was observed, with restoration of periodontal health, although the paresthesia had persisted. We describe this case, present a review of the relevant published data, and discuss the possible causes, diagnosis, treatment, and follow-up protocol of mandibular osteomyelitis caused by arsenic trioxide.