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Biomedical subjects

B L Dahl

Publications and source records attributed to B L Dahl.

At least 37 records · Page 2Linked to original sources

An index for evaluating wear of teeth.

An index for evaluation of dental wear based on Ryge's system comprising three satisfactory and two not acceptable categories was tested in two different age groups of individuals with brain damage. Group 1 consisted of 12 individuals, 3 women and 9 men, with a mean age of 34.5 years. Group 2 consisted of 13 individuals, 4 women and 9 men, with a mean age of 45.1 years. The wear was evaluated by three examiners, two dentists and one dental hygienist. The examiners worked independently, having available at all times the written criteria and a photographic guide illustrating the lowest limit of each category. Each tooth was given a rating in accordance with the index, and the interexaminer agreement of 612 such evaluations was approximately 85%. Each person was given an individual wear rating corresponding to the most severe category comprising 90% of the tooth ratings. The difference in the distribution of individual ratings between the two groups was tested for significance by the ridit method. Significantly greater wear was observed in group 2 than in group 1, indicating a good sensitivity of the index.

Adult↗

[Bruxism].

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Bruxism↗

Bonding properties and dimensional stability of hydrocolloid impression systems in fixed prosthodontics.

Four hydrocolloid impression systems for fixed prosthodontics and one conventional alginate were tested for bonding properties between the syringe and the tray materials of the systems. Their dimensional stability was tested also after the impressions were kept in a humidor for 1, 3, and 24 hours before casts were poured. Findings showed that there was a true bond between the syringe and the tray materials for all combinations. The precision tests gave a mean percent difference between the master model and the cast of less than 0.15 for all material combinations at both the 1- and 3-hours observations. The same was true at the 24-hours observation, except for one combination. From a clinical point of view, all the materials can be used for fixed prosthodontic impressions even if kept for 1 and 3 hours in 100% humidity before pouring the casts; however one material was unsuitable if kept for 24 hours before pouring.

Alginates↗

Long-term observations of an increased occlusal face height obtained by a combined orthodontic/prosthetic approach.

Twenty individuals received an increased occlusal face height by orthodontic means (a partial bite-raising splint). After splint treatment some of the anterior teeth were capped at the new occlusal face height. The average increase from start of splint treatment till after crown cementation was 1.9 mm. The stability of the vertical relations of the face after this treatment was studied. The average observation time was 67 months, i.e. 5.5 years. The modes of reaction were highly individual. A certain average relapse of the occlusal face height did occur, mostly in the course of the first 6 months after crown cementation. However, in no case did the increased face height revert to basis. In the period from 6 to 67 months after crown cementation twelve out of nineteen patients showed practically completely stable vertical relations.

Adolescent↗

Pathologic attrition and maximal bite force.

The maximal bite force was recorded between antagonizing anterior teeth in a group (n = 10) of patients with pathologic attrition and in a control group. No statistically significant difference between the maximal bite forces was recorded. Also, the effect on the maximal bite force of the continuous wearing of a partial bite raising splint for 4 months was recorded. The great individuality in reaction patterns prohibited simple generalizations. However, in some individuals the maximal bite force was larger when biting on the splint than without, both at base line and after 4 months. Also, the maximal bite force showed a tendency to increase with time. The findings indicate that pathologic attrition is not necessarily associated with a high maximal bite force. Also, the maximal bite force recorded under various conditions is seemingly not an absolute value but rather the result of a number of factors of varying importance for different individuals.

Adult↗

Clinical study of two luting cements used on student-treated patients: an interim report.

A long-term clinical test has been started to compare a zinc phosphate with a polycarboxylate cement as luting materials for crowns and fixed partial dentures. The present report includes an evaluation of two groups of student-treated patients regarding their suitability for this type of testing, as well as certain clinical and radiographic criteria recorded 6 and 18 months after insertion of the restorations. No significant differences were observed regarding the composition of the patients or the type of treatment. No loosening of restorations and no differences between the two groups in other respects such as subjective complaints, clinical symptoms, carious lesions, or periapical changes were observed. So far, both cements seem equally suitable as luting materials.

Adult↗

The effect of a partial bite-raising splint on the inclination of upper and lower front teeth.

In a previous paper it was maintained that the effect of the permanent use of an anterior partial bite-raising splint was an intrusion of the front teeth and an eruption of the others. However, the effect might have been merely a change in the inclination of the front teeth. The present study comprised the same material as earlier. Linear and angular changes in the position of upper and lower incisors were measured on cephalometric radiographs. In the upper jaw a possible average proclination occurred, whereas in the lower jaw no or only a very small retroclination took place. The values were well within the method error, and it was concluded that the effect of the splint had been one of intrusion of the upper and lower front teeth and not merely a change in their inclination.

Adolescent↗

The effect of a partial bite raising splint on the occlusal face height. An x-ray cephalometric study in human adults.

20 patients (18 - 50 years) with pathological attrition of upper and/or lower anterior teeth were treated, as a temporary measure, by means of a partial chrome-cobalt splint covering the palatal surfaces of the six upper front teeth. Tantalum implants to provide reference points were placed in the basal portion of upper and lower jaw bones. Lateral cephalometric radiographs were taken with and without the splint at the beginning of treatment and thereafter every two months till the difference between measurements was as small as possible. Changes in the occlusal face height were evaluated. Measurement reliability proved to be very high. Continuous use of the splint caused intrusion of the front teeth and eruption of the others in all patients. The intrusion was on an average 1.05 mm and the eruption 1.47 mm after 6 - 14 months, indicating a possible potential for tooth eruption in human adults. More eruption than intrusion appeared to take place in the youngest age groups. Sexual differences could not be established. Use of the splint did not cause the common symptoms of mandibular dysfunction. Lisping was the most serious complaint.

Adolescent↗

Some self-reported symptoms of temporomandibular joint dysfunction in a population in Northern Norway.

The distribution of a number of self-reported symptoms of temporomandibular joint (TMJ) dysfunction, parafunctions and treatment behaviour was studied by means of a questionnaire answered by 94% of a population group of 358 persons aged 20-69 years in Northern Norway. Nine subjects reported pain from the temporomandibular joint (TMJ) when opening their mouth and/or when chewing, while twenty-one subjects had clicking sounds in the TMJ. Seventeen persons had been grinding their teeth during the previous week. Only seven individuals had ever sought medical or dental advice because of TMJ disorder. Tooth grinding and symptoms of TMJ dysfunction were most common in young people, in people with twenty teeth of more and/or in people from high social classes, whereas differences according to sex and income were small. The low frequency of subjective symptoms of TMJ dysfunction and parafunctions in this population was related to demographical, social, dental and methodological influences.

Adult↗

Tissue hypersensitivity to dental materials.

Five cases of tissue hypersensitivity to Scutan and two to Impregum are reported. The reaction to Scutan was a burning sensation in the mucosa in contact with the material, followed by swelling and erythematous ulcers producing heavy discomfort. All symptoms gradually disappeared after removal of the material. To Impregum the reaction was basically the same, only less vigorous since contact with the material is of limited duration. All the cases were women in the menopause. Attention is drawn to the possibility of hormonal imbalance being a factor of importance in the development of hypersensitivity reactions to materials of this sort.

Aged↗