Showing papers in "Journal of Prosthetic Dentistry in 1953"

The speaking method in measuring vertical dimension

Abstract: The speaking method of measuring vertical dimension is a physiologic phonetic method which measures vertical dimension by means of the closest speaking space. This space is measured before the loss of the remaining natural teeth to give us the patient's natural vertical dimension which can be recorded and used at later dates. The same closest speaking space should be reproduced in full dentures as is found in the natural dentition. This space is also the means of proving that vertical dimension must not be increased. It is advisable to measure and record the closest speaking space of all patients after they are past 20 years of age, for possible use in later years. For example, if we should feel that a certain patient might need occlusal reconstruction the measurement of the closest speaking space can be made which can be compared to the space existing in earlier years. If this space should be larger during later years in life, it could be assumed that the vertical dimension was decreased, and treatment needed to increase the vertical dimension with occlusal reconstruction. This is an assumption based on the hope and feeling that the speaking method with its closest speaking space will prove constant throughout life, as records seem to indicate at the present time. The measurement of vertical dimension by use of the speaking method with its closest speaking space has been found in my experience to be the missing link in successful full denture construction. It will prove most valuable to dentists doing occlusal reconstruction and to periodontists in the treatment of their patients.

Force analysis of prosthetic appliances during function

Abstract: A study has been conducted to evaluate the vertical forces that are placed on the teeth of full and partial dentures during mastication. Relatively small forces were required for the mastication of most foods commonly found in the diet. Maximum forces up to 12 kg. have been recorded while chewing rolls and certain breads in the prosthetic situations. Six to eight kilograms were the most common maximum forces required. Most foods required an average force ranging from 0.3 to 1.8 kg. for mastication. Even though the average maximum biting force that denture wearers can exert is approximately 12 kg., they still possess an adequate force capacity to masticate the great variety of foods appearing in the diet. Full denture and partial denture wearers utilized similar forces during mastication. Ingestion of liquids with certain foods by two denture wearers reduced the maximum forces and the total kilogram strokes used during mastication by about one-half. Cooking foods reduced the maximum forces by 50 to 75 per cent and also reduced the total forces needed to reach the swallowing point by 83 to 96 per cent.

Occlusal plane relation to facial type

Abstract: 1. The historical background revealed by checking literature dating from 1839 to the present on the problem of orienting the occlusal plane of artificial dentures shows slight agreement in concept. 2. Two hundred lateral cranial roentgen ray projections of senior dental students were studied to determine whether or not a correlation exists between facial type and occlusal plane location of natural dentitions. The Broadbent-Bolton Cephalostat and other well-established methods were used in the study. 3. Extensive biologic and physiologic experiments have established the functional relationship of muscle tissue to osseous and dental tissues, muscle tissue appearing to hold sway over the hard tissues. 4. Classifying maxillomandibular relations by the method proposed by Simon limits potential error in the problem. In reality, it indicates the relative direction of muscle tension dependent on the location of muscle to bone attachment. 5. The mean values of the landmarks investigated show definitive characteristics. On exposing these findings to statistical evaluation, the majority of results bear out as being statistically significant in 21 out of 28 values measured. 6. The study indicates a strong correlation in the location of the occlusal plane of natural dentitions to given facial types, in lateral aspect. 7. Additional data gleaned during the investigation reveal the location of the anterior teeth to the occlusal plane according to facial type. The position of the tongue to the hard palate with the teeth in centric occlusion is also tallied.

Masticatory function of partial denture patients among navy personnel

Abstract: Masticatory function has been studied among 103 partial denture patients before and up to one month after completion of the prosthetic restorations. Their average masticatory efficiency and food pulverization were compared with the average for 42 full upper and lower denture patients one month after insertion, with 68 standard dentition patients, and with 27 partial and full denture patients who had had nine plus month's use of the restorations. Function measurements were made before surgery, before insertion, after insertion, ten days later, and thirty days later. At each period tests on masticatory performance were made for each half of the dentition, strokes required to prepare this food for swallowing were counted, and the degree of pulverization of the food was measured. Patients selected for partial dentures had definite need of restorations, since their efficiencies averaged from 16 to 18 per cent of a standard dentition before surgery was performed. The average efficiencies for all groups rose immediately after the restoration was placed in the mouth, and more gradually thereafter, reaching the maximum efficiency in approximately one month. At this time the most efficient group was small partial dentures in the first molar region (adding 6, 46, or 56) which occluded against the natural dentition. Their efficiency was 63 per cent of standard dentitions tested at the same location. All other partial dentures occluding against a natural dentition average 39 per cent in efficiency at this time. Partial dentures occluding against an artificial dentition averaged 24 per cent in efficiency and were practically the same as full dentures one month after insertion. Tooth-borne partial dentures and free-end saddles had the same efficiency on the average. The increase in efficiency caused by the partial dentures allowed the patients to obtain finer pulverization of food on the average before swallowing, with the more efficient groups showing better pulverization. The better preparation of the food was achieved with less effort by the patient as indicated by use of fewer masticatory strokes.

A guide to the orientation of the plane of occlusion

Abstract: 1. Cook's plane forms an angle with the plane of occlusion which falls within predictable limits. 2. The angle formed by Cook's plane and the plane of occlusion is related to the distance from the anterior nasal spine to the hamular notch. The greater the distance, the more acute the angle; the shorter the distance, the more obtuse the angle. 3. Though there is a certain bilateral asymmetry in the skulls and casts measured, it is negligible in its effect on the basic correlations. 4. Though the distances from the anterior nasal spine and the hamular notches to the plane of occlusion varied, the difference between the two measurements approached a constant, enough to permit the practical use of the average value. 5. Within esthetic considerations, the anterior aspect of the plane of occlusion should be kept parallel to the pupils of the eyes.

The ABC classification of partial denture segments

Abstract: At this point in the analytic procedure, recognition of the three basic segment types, notation of whether they are discrete from other missing segments or continuous, and an estimate of the length, is adequate This minimum number of basic classes will permit adequate description of any partial denture situation It is an approach to a natural classification, to a consideration of the functional essence of the elements classified Its purpose is identical with the aim of all knowledge—to refine our expectations and make our predictions more reliable By this means it may serve as a guide to research

An improved temporary acrylic fixed bridge

Abstract: T HE purpose of this article is to suggest an improved and simplified method of constructing acrylic bridges and splints prior to the preparation of teeth. The current techniques, as described by Talkov’, fall short of the ideal. In order to overcome the disadvantages of the techniques already in use, a new technique was devised. It makes possible the construction of a temporary acrylic bridge or splint of eggshell thickness, which is an exact duplicate of the original anatomy or any modification of it. Construction time is a matter of minutes; the bridge or splint is ready for use before the abutment teeth are prepared. Appropriate incisal, body, and gingival shades of acrylic can be used where indicated.

Operative procedures and the tooth

Abstract: 1. The exposed pulp can be satisfactorily protected from irritating filling materials with the immediate application of a calcium hydroxide paste or nonirritating metallic filling material. 2. Since it is difficult to detect minute pulp exposures with the naked eye the deep cavity should not have applied to it irritating chemicals. 3. Wherever possible, a calcium hydroxide paste should be used in deep cavities between dentin and irritating filling materials. 4. There was no apparent difference in the effect upon the tooth between cavity preparation with the steel bur and the airbrasive techniques.

The influence of saddle classification on the design of partial removable restorations

Abstract: The primary consideration in partial denture construction is to distribute the forces on the occlusal surfaces with the minimum damage to the supporting tissues. This is accomplished with the aid of a detailed examination consisting of a clinical and roentgenopraphic examination, and an examination of study casts. The application of the data thus obtained leads automatically to a classification descriptive of the type of support each saddle permits. Class 1 saddles provide tooth support which gives trouble-free, comfortable service. Class 2 saddles and those Class 3 saddles treated as tissue borne provide fair to good support, but usually require relining at intervals of from two to four years in order to maintain efficiency. With the Class 3 or problem type of saddle, the result will depend in a very large measure upon the skill, knowledge, and experience which the operator can bring to bear upon the individual problem. If the operator has classified the saddles correctly, the prognosis of the vast majority of dentures is a foregone conclusion, and the design and construction can proceed with every confidence of a successful result.

Anatomic versus nonanatomic teeth

Abstract: Teeth for dentures differ so radically from natural teeth in the firmness of their attachment to the jaw that special designs are required to help stabilize them during chewing. The development of special occlusal patterns for denture teeth awaits the application of engineering methods by competent industrial designers under dental supervision. It can be predicted that the result of their efforts will be a “functional design,” notable for “fitness for use” under realistic conditions. Such a functional design will minimize the displacement of denture bases (especially the lower) which is so traumatic to the alveolar mucosa during mastication.

The physiologic approach to partial denture design

Abstract: Impression making is an extremely small part of the professional service rendered in partial dentures. The planning and diagnosis for partial dentures and the preparation of the mouth have not been within the scope of this article. However, the importance of these steps is emphasized. The professional service in partial denture work consists of three steps: planning (diagnosis), preparing the mouth, and designing. To properly design a partial denture requires a background of periodontology, oral histology, and physiology. The construction of a partial denture is a mechanical operation, but the designing of a partial denture is not. The principles of partial denture construction are summarized as follows: 1.1. Provide adequate support on the remaining natural teeth to resist vertical stresses, and to direct those stresses in the direction of the long axes of the abutment teeth. 2.Provide broad coverage of saddle areas so the stresses borne by the soft tissues are distributed over a large area. 3.Provide adequate tooth-borne resistance to lateral stresses (adequate both in rigidity and in number of teeth engaged, so that this stress is distributed over a number of abutments). 4.Provide adequate retention. 5.Provide for distribution of stress between the relatively rigid abutment teeth and the relatively resilient saddle areas. 6.Have rigid bars and connectors. 7.Avoid covering the free gingival margin around the remaining teeth with denture base or connectors. 8.Decrease the occlusal table by using narrower artifical teeth and fewer teeth. 9.Provide harmony of the occlusal surfaces of opposing teeth, both natural and artificial (this includes recording true centric relation, obtaining as balanced an occlusion as possible, and reducing cuspal inclines to minimize lateral stress). 10.Place the denture teeth over the ridge or lingual to it.