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Biomedical subjects

J B Woelfel

Publications and source records attributed to J B Woelfel.

10 recordsLinked to original sources
PubMed1992

Root form and canal anatomy of maxillary first premolars.

The external and internal anatomy of 240 extracted, maxillary first premolars was studied. The external anatomy was studied by measuring each tooth and by observing the direction of the root curvatures from the facial and proximal aspects. The internal anatomy of the pulp cavity was studied by a method of making the teeth translucent. A total of 55.8% of the teeth had a single root, 41.7% had two roots and 2.5% had three roots. Considering all of the first premolars, 17.1% had one canal, 80.4% had two canals and 2.5% had three canals.

Bicuspid↗
PubMed1992

A laboratory assessment of recording reliability and analysis of the K6 Diagnostic System.

This laboratory study investigated the recording reliability and analysis of the K6 Diagnostic System, a computerized instrument that records mandibular movements in three planes. Two special devices were utilized for this purpose, one commercially available and the other designed and constructed by the authors. These devices could produce linear movements and simulate head and mandibular movements, respectively. The largest distortion of the simulated mandibular movements was found in the frontal plane tracings of simulated chewing patterns. For the linear movements in an x-axis, the error of the analyzed K6 system ranged from 9.4% to 30% and in a z-axis from 0% to 15%. A considerable degree of head movement was required to produce a significant error on the K6 measurements.

Analysis of Variance↗
PubMed1992

Morphologic study of the maxillary molars. Part II: Internal anatomy.

The internal anatomy of three hundred and seventy (370) decalcified and cleared human maxillary molars was studied. Seventy-five percent of the first molars, 58% of the second molars and 68% of the third molars studied presented three (3) root canals and 25% of the first molars, 42% of the second molars and 32% of the third molars presented four (4) root canals. The authors observed that the incidence of two root canals in the mesiobuccal root was higher in second maxillary molars than in first maxillary molars.

Dental Pulp Cavity↗
PubMed1991

Suggested modifications for the leaf wafer system.

The Woelfel leaf wafer system provides an easy and accurate way to register centric relation position, which is important in dental practice. This article suggests the following modifications of the system that should enhance the accuracy and convenience of the technique: (1) custom deform wafer before deprogramming or tripodizing the mandible, (2) mark position of leaf gauge at wafer slot, (3) secure leaf gauge to wafer with cyanoacrylate glue, and (4) write pertinent information on paper leaf gauge.

Centric Relation↗
PubMed1991

Morphologic study of the maxillary molars. 1. External anatomy.

The authors studied the external anatomy, root curvature and degree of root fusion of 744 maxillary first, second and third molars. The root lengths and root curvatures were quite similar on the first and second molars with their lingual roots curving toward the buccal on 54.6% and 52.3% of them, respectively. Complete separation of all three roots was observed on 86.4% of the first molars, 75.9% of the second molars and on only 18.8% of the third molars.

Humans↗
PubMed1990

Denture base acrylic resins: friend or foe?

This article reviews the advantages and disadvantages of denture base acrylic resins. Improvements in areas such as strength and speed of cure are discussed. The authors also emphasize the necessity for investigating the effects of factors other than denture base materials on the incidence of troublesome dentures.

Acrylic Resins↗
PubMed1977

Processing complete dentures.

The processing of acrylic resin dentures is an exacting art but is relatively simple to carry out to perfection day after day, even when several dentures are processed at the same time. Nine salient factors in the proper processing of acrylic resin dentures were sequentially listed. Unfortunately, a number of these technical procedures are frequently overlooked or shortcuts may be substituted. Herein lie the causes of some hitherto unexplained clinical failures attributed to the acrylic resin denture base material. The acrylic resin denture base materials have been and are currently the best plastic for making dentures. This material has many unique assets and few faults. Its fine properties are often overlooked by the dentist who has several edentulous patients experiencing problems with dentures he made for them. Sore spots, faulty occlusion, looseness, and even breakage are most likely due to inadequate mouth conditioning or poor impressions, incorrect jaw relations, or the dentist's failure to remount the dentures prior to insertion. We have sufficient knowledge and scientific evidence to realize that most, if not all, denture problems are caused by the dentist's technique or by dentist-patient relationship. These problems should not be attributed to the acrylic resin material nor to the hard-working, conscientious dental laboratory technician. I doubt that more than 2 per cent of all complete denture difficulties experienced by frustrated patients would be solved by the introduction and availability of a new perfect denture base material.

Acrylic Resins↗
PubMed1976

Five-year cephalometric study of mandibular ridge resorption with different posterior occlusal forms. Part I. Denture construction and initial comparison.

The average 5 year reduction of the occluding vertical dimension (nasion to menton) for 45 patients was 3.2mm. (2.8 mm. for the anatomic group, 3.2 mm. for the semianatomic group, and 3.6 mm. for the nonanatomic group, each constituting 15 patients). Mandibular physiologic resting face height became foreshortened on the average only one third as much as the morphologic centric occlusion face height. Tabulation of adjustments for sore spots indicated that: the fewest postinsertion appointments were required for the anatomic group of patients; three fourths of 604 denture base alterations were on lower dentures; for upper and lower denture base alterations, one third were made on the borders and two thirds, on the basal seat; one sixth of all alterations were made at routine recall examinations; the fewest upper denture base alterations were for the nonanatomic patients; and the fewest adjustments of the lower denture base on the tissue surface and on the borders were done for the anatomic group of patients. This investigation has been underway for 18 years, and several more re

Adult↗
PubMed1975

A longitudinal study of rest position and centric occlusion.

A fifteen-year longitudinal study of rest position and centric occlusion was done on sixteen dentulous subjects with random occlusions. In reviewing the literature the author could find no other investigation with this number of years interim. Records consisted of lateral cephalometric roentgenograms taken when the patient was in rest position and in centric occlusion. Rest position was determined by the patient saying "m" and swallowing, and electromyographically when the anterior belly of the digastric and the temporalis muscles elicited the electrical activity. Both linear and angular measurements were made. The figures from 1958, 1959, and 1960 were averaged and compared with the mean of those taken in 1973. Rest position was found to have a small range of stability in all subjects, while the vertical dimension of centric occlusion increased in ten subjects, decreased in two, and remained the same in four.

Cephalometry↗