Part-Digitizing System of Impression and Interocclusal Record for Complete Denture Fabrication.

Few studies have reported the application of digital technology to removable dentures, particularly for the process of impression and interocclusal recording for complete denture fabrication. This article describes a part-digitizing system of impression and interocclusal records for complete denture fabrication. The denture foundation area in an edentulous mouth, including the border areas and residual ridge, is outlined by tracing the surfaces with a 3-D pen-type digitizer. Specialized trays for final impressions and interocclusal records were generated using computer-aided design and manufactured using the digital data. Final impression and interocclusal records were carried out using these specialized trays. The computer-aided method using preliminary digital impressions and specialized trays would be feasible for clinical use for complete denture fabrication.

A Pilot Study on the Dentoalveolar and Skeletal Effects of Two Functional Appliances in Class II, Division 1 Growing Children.

UNLABELLED: The aim of this preliminary study was to compare the dentoalveolar and skeletal effects of two different Removable Functional Appliances (RFAs) in growing Class II, Division 1 subjects based on pre- and post-treatment cephalometric analyses. Forty subjects with Class II, Division 1 malocclusions were recruited from the undergraduate orthodontic clinic at the University of British Columbia for this clinical trial. All subjects were selected under the same inclusion and exclusion criteria and full orthodontic records were obtained for each subject. They were divided into two groups: 20 (12 males) in RFA-1 group and 20 (14 males) in RFA-2 group. RESULTS: There were no significant differences between the RFA-1 and RFA-2 groups in insertion age (10.4 ± 1.3 years and 10.7 ± 1.4 years, respectively) or treatment duration (163 ± 6.7 months and 16.1 ± 65 months, respectively). There was no significant difference in cephalometric variables between the two groups at baseline. After treatment, both groups demonstrated a statistically significant (P < 0.05) increased SNB and L1-Apo; decreasedANB, Wits, overjet and overbite. CONCLUSIONS: The functional effects of RFA-1 and RFA-2 are comparable in Class II, Division 1 pre-adolescent patients in the same age group. The RFA-1 is effective in generating treatment changes as the suggested wear time was only during sleep.d.

Effectiveness and fabrication of mouthguards.

Although mouthguards have been suggested as a means for preventing dental traumatic injuries, there are still some controversies over some aspects such as effectiveness in preventing concussions, material selections, method for fabrication, design, side effects and so on. The purpose of this literature review was to clarify differences in opinions with supporting evidence on these issues and find the best guidelines for promoting usage and providing mouthguards with better protective capability and fewer side effects such as difficulty in breathing and speaking.

The Geniohyoid Muscle Directly Affects Masticatory Function: Evaluation with Decision-Tree Analysis.

PURPOSE: To clarify the effect of geniohyoid (GH) muscle morphology and related function on masticatory ability using a decision-tree analysis. MATERIALS AND METHODS: A total of 103 participants were enrolled. A cross-sectional area (CSA) of the GH muscle, neck circumference, body mass index, tongue pressure, jaw opening strength, and masticatory ability score were measured. The CSA of the GH muscle was selected as an independent variable for the first layer of the decision tree, with masticatory score as the dependent variable. RESULTS AND CONCLUSION: These data suggest that the CSA of the GH muscle may have a large impact on the masticatory ability score when evaluating masticatory ability.

[Stress releasing effect of tissue conditioning materials for interim dentures after implant installation].

PURPOSE: The main objective of this study was to examine the influence of the thickness and its longitudinal change within the limited denture space on the stress releasing effect for installed implants during the healing period of a two-stage procedure. METHODS: As for the tissue conditioning material, Tissue Conditioner (Shofu, Kyoto, Japan) with the designated powder liquid ratio was used. The force transmitted to the implant with the material 5 min after the mixing was measured by a miniature pressure sensor in the position of the implant head (Kyowa, Tokyo, Japan). Measurements were repeated with the material preserved in the water for one and two weeks. Load of 2 kg was applied with a 3-mm diameter round tip using a static loading machine for 2 min to the center of the flat type denture model. The model consisted of denture, mucosa, tissue conditioning material and implant where the first three variables were changed as in the oral cavity. Influence of thickness of each variable was examined longitudinally. RESULTS: Force measured with any thickness of tissue conditioning material was smaller than that without the material. The stress releasing effect did not change with change of the longitudinal material property up to two weeks. CONCLUSIONS: Within the limitations of our study, it was suggested that the stress releasing effect of the tissue conditioning material for the installed implant was not influenced by the thickness or change of longitudinal property.

Movement of the mandibular condyle and articular disc on placement of an occlusal splint.

OBJECTIVE: The aim of this study was to evaluate, with the use of magnetic resonance images, mandibular condyle and articular disc movement on occlusal splint application. STUDY DESIGN: Thirty-five subjects were classified into "Pain" and "No-pain" groups based on visual analog scale scoring of temporomandibular joint (TMJ) pain and were categorized as bilateral normal disc (ND), unilateral anterior disc displacement (ADD), or bilateral ADD position. t test and analysis of variance with multiple comparisons were used for statistical analyses. RESULTS: Pain and No-pain groups showed significant anteroinferior and rotated movement of the condyle on splint application, but the disc did not significantly move in the Pain group. Of all groups, anteroposterior movement of the condyle and disc with the splint was significantly less in the unilateral ADD group. CONCLUSIONS: TMJ pain was associated with decreased movement of the articular disc. Disc and condyle movement was different in the unilateral ADD group in the presence of a splint compared with the ND and bilateral ADD groups.

Composite resin root coping with a keeper for magnetic attachment for replacing the missing coronal portion of a removable partial denture abutment.

Numerous methods for replacing missing removable partial denture abutments have been introduced, however, most of them are time consuming and require several visits to complete the procedure. Since magnetic attachments can provide support and bracing as well as retention for overdenture abutments, the remaining tooth root structure can be used to support the coping with the keeper. Through the use of composite resin and adhesive material, improved retention of the keeper to the root may be achieved, along with improved esthetics. This article describes a method for replacing the missing abutment of a removable partial denture with a magnetic attachment, and a composite resin coping with a keeper.