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Biomedical subjects

B D Monteith

Publications and source records attributed to B D Monteith.

At least 19 recordsLinked to original sources
PubMed2004

The bitewing radiograph as an assessment tool in fixed prosthodontics.

Molar crown preparations, as described in the literature, have standard forms dictated by the demands of retention, resistance and the physical properties of materials. Standard designs may not be appropriate for all patients because of ethnic variations in tooth shape, pulp size and dentine thickness. Accurate data on these features could assist clinicians to minimize the risk of accidental pulpal injury. The aim of this study was to compare the first molar crown and pulp dimensions between Asian (Chinese, Korean, Malay) and other ethnic groups, using measurements from the bitewing radiographs of 121 subjects. Comparisons revealed the following significantly different features of Asian first molars: larger total pulp areas in uppers (P < 0.0005); shorter crowns (P < 0.0005); narrower upper teeth at the cervix (P < 0.0005); wider pulps at the cervix of lowers (P < 0.02); more bulbous crowns (P < 0.0005 for uppers; P < 0.01 for lowers), and finally significantly thinner dentine interproximally at the cervix (P=0.001 for uppers; P=0.011 for lowers). Preparations with wide shoulders could pose hazards to the pulps in Asian subjects. This study emphasizes the value of bitewing films in assessing crown and pulp size and shape before making crown preparations. The experienced practitioner may intuitively include tooth and pulp morphology in treatment planning, but this appears not to be taught or documented in textbooks.

Adult↗
PubMed2004

Pulp size in molars: underestimation on radiographs.

The aim was to determine whether radiographs provide a clinically useful indication of pulp size in diseased/restored human first molar teeth, and to investigate accessibility of pulp tissue for diagnostic testing using laser Doppler flowmetry (LDF). Extracted teeth of known age were collected. Restorative materials were removed and teeth with evidence of pulp exposures excluded. Fifty-six teeth were radiographed from buccal and mesial aspects, and then their crowns were sectioned axiobuccolingually and photographed. Images were digitally scanned and measurements made of the total pulp area (above a line across the most superior part of the pulpal floor) and the pulp area in the clinical crown (superior to a line between the amelocemental junctions). The pulp width at the cervix and the highest point of the pulp were also recorded. Data were analysed using Pearson correlations. Pulp areas within the clinical crowns were significantly larger than indicated by radiographs, by 23% in the case of the clinically attainable buccal view (P < 0.05). Pulps may be more accessible to flowmeter testing than they appear. Absence of pulp tissues in the crown was recorded in equal numbers of teeth on radiographs and sections, but with agreement for only one tooth. Sixteen per cent of the teeth had no pulp area in the clinical crown when sectioned, but might still be suitable for testing using LDF.

Adult↗
PubMed2003

Coronal pulp size in molars: a study of bitewing radiographs.

AIM: To: (i) study coronal pulp dimensions in human first molar teeth; (ii) investigate the effects of restorations on pulp size; (iii) determine differences in dimensions between teeth of Mongoloid patients and teeth of other ethnic groups; and (iv) record the presence of pulp stones. METHODOLOGY: Bitewing radiographs of 121 subjects (mean age, 20.9 years) were taken under standardized conditions. The films were digitally scanned and nine measurements were made from the image of each first molar. The data were analysed in terms of presence or absence of restorations and in terms of racial group. Differences were examined using Student's t-test, Pearson correlations and Levene's test. RESULTS: A total of 445 teeth were analysed. Large crowns were correlated to large pulps. Teeth restored with occlusal and proximal restorations had significantly smaller pulps (P = 0.044 and 0.004, respectively), but no difference was found in pulp area in the clinical crown between the restoration types. Mongoloid crowns were shorter and more bulbous. Pulp areas of maxillary molars and pulp widths at the cervix of mandibular molars were significantly larger in Mongoloids. The pulp area in the clinical crown correlated to pulp horn height for Mongoloids and others and for maxillary and mandibular teeth. No differences were found between the heights of pulp horns in the Mongoloid and other teeth. Four of the pulp measurements demonstrated sexual dimorphism. Stones were present in almost 10% of the subjects, representing 4% of the tooth pulps examined. CONCLUSION: Even teeth with shallow occlusal restorations had reduced pulp spaces. There were significant differences in pulp and crown dimensions between the teeth of Mongoloid patients and those of other patients.

Adolescent↗
PubMed1998

Organizational considerations for an electronic curriculum. Part II: A multimedia approach to dental education in general and to prosthodontics in particular.

STATEMENT OF PROBLEM: In using multimedia electronic knowledge-transfer as a tool in dental education, an overriding concern has centered on how to devise an organizational model that will accommodate the vast and diverse arrays of information involved, yet be sufficiently simple to provide students with a rational and consistent means of accessing the information they require. PURPOSE: This article presents a model that adopts the Natural History of Dental Diseases as the organizing principle. This article also encourages a mindset in prosthodontics that focuses on the dynamics of energy-dispersal through the supporting structures, in an attempt to provide learners with a deeper cognitive dimension for problem solving and to facilitate their empowerment as life-long learners.

Computer-Assisted Instruction↗
PubMed1998

Organizational considerations for an electronic curriculum. Part I: A rational nosology for concept management in dentistry.

STATEMENT OF PROBLEM: With the use of multimedia electronic knowledge as a tool in dental education, an overriding concern has centered on how to devise an organizational model that will accommodate the vast and diverse arrays of information involved, yet be sufficiently simple enough to provide students with a rational and consistent means of accessing the information they require. By adopting the natural history of the diseases dentists are called on to address as a common organizing principle, it becomes possible to link all concepts that relate to individual problem areas through a technique of retro-mapping. PURPOSE: The purpose of this article is to introduce learners to a cognitive "scaffolding" that will assist them in achieving a deeper cognitive dimension for problem solving.

Curriculum↗
PubMed1993

Minimizing biomechanical overload in implant prostheses: a computerized aid to design.

Implant-supported prostheses must be able to withstand the load capabilities of individual patients to overload them. The gold alloy screw in the Brånemark system is by intention the weakest component. Therefore, if cantilever lengths can be designed so that occlusal forces distributed to individual fixtures are limited to the gold screws' ability to accept them, breakage-free performance may be assured. Models, such as that of Skalak, are capable of developing the required analytical processes to provide the information necessary to achieve this design. Unfortunately, the overt mathematical complexity of the Skalak model has militated against its routine use in the operatory. Its computational aspects are, however, eminently suited to computerization and indeed provide the basis for the computer program that is described in this article. This program is simple to apply clinically and, when used in conjunction with available load parameters of gold screw performance, can provide the clinician with a routine and scientific basis for rational implant prosthesis design.

Bite Force↗
PubMed1984

Management of loading forces on mandibular distal-extension prostheses. Part I: Evaluation of concepts for design.

The viscoelastic reaction of ridge mucosa and abutment teeth, by virtue of their periodontal ligaments, is a necessary dimension in the evaluation of design concepts for removable partial dentures for patients with distal-extension ridges. The possible modalities are (1) removable partial dentures with flexible denture bases (stressbreakers), (2) use of a floating denture base impression technique, (3) use of a mucofunctional impression technique to relate the denture base to the framework, and (4) use of an endosseous implant. An evaluation of each modality has been made.

Alveolar Process↗
PubMed1984

Management of loading forces on mandibular distal-extension prostheses. Part II: Classification for matching modalities to clinical situations.

When a mandibular distal-extension removable partial denture is planned, consideration should be given to the capacity of the supporting structures to accept the functional loading of the prosthesis. To prescribe a treatment modality that will not cause their breakdown, an analysis should be made of the relative strength and weakness of the ridges and abutment teeth. This judgment can be visualized by classifying partially edentulous jaws into one of the four categories that are possible when the two key factors of ridge resistance and abutment teeth are combined.

Alveolar Process↗
PubMed1983

The determination of free-way space in edentulous patients: a cephalometric approach.

This study was prompted by the hypothesis that the contractile power of the masseter and medial pterygoid muscles influences not only the shape of the gonial angle of the mandible into which these muscles insert, but also that they play a major part in determining the amount of free-way space present in any individual. Tracings were made from the lateral cephalograms of 130 dentate subjects and the gonial angle measured in each case. Free-way space was also measured, using a dakometer, and the paired values subjected to statistical analysis. A strong inverse correlation was found to exist, indicating that throughout the sample a decrease (or sharpening) of the gonial angle is accompanied by a predictable increase in the free-way space. By applying the processes of linear regression to the paired results, a formula was obtained which may be used to predict the best value of one variable for any given value of the other. Thus, in an edentulous case, where the value of the free-way space measurement is unknown, a method is provided for predicting its best value by the determination of the patient's gonial angle through cephalometric analysis.

Adult↗