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Biomedical subjects

R Lehtinen

Publications and source records attributed to R Lehtinen.

At least 37 records · Page 2Linked to original sources
PubMed1991

Penetration of erythromycin into periapical lesions after repeated doses of erythromycin acistrate and erythromycin stearate: a pilot study.

In 26 patients who had undergone apicectomy and extirpation of granulomas (n = 9) or radicular cysts (n = 17), concentrations of erythromycin, 2'-acetyl erythromycin, and their anhydro forms were determined with a novel chemical method in plasma and periapical lesions after at least 2 days of treatment with erythromycin acistrate (EA) (400 mg three times daily, n = 11) or erythromycin stearate (ES) (500 mg three times daily, n = 15). Oral surgery was performed 2 1/2 to 3 hours after the last dose. Blood samples were collected at the time of operation, and immediately before antibiotic treatment, and 1, 2, and 6 hours after treatment. At all time points EA produced at least twice the total antibiotic (2'-acetyl erythromycin plus erythromycin) concentrations in plasma as ES. Erythromycin levels in plasma were at least as high after EA treatment as after ES. In periapical lesions erythromycin concentration after EA was three times higher (1.34 +/- 0.28 micrograms/gm) than after ES treatment (0.40 +/- 0.17 micrograms/gm). Although the total drug concentration in periapical lesions was about the same after EA (2.64 micrograms/ml) and ES (3.41 micrograms/ml), most of the drug recovered after ES was antimicrobially inactive anhydroerythromycin (3.01 micrograms/gm). The concentration of anhydroerythromycin in plasma was approximately the same as that of erythromycin after ES throughout the dose interval. After EA treatment both plasma and the periapical lesion samples contained hardly detectable amounts of anhydroerythromycin. Hence EA has a good bioavailability essential for treatment and prophylaxis of bacterial infections in dentistry.

Adult↗
PubMed1991

Clinical aspects of oral implantology.

During the past few decades the use of implants in dentistry has increased markedly. Endosteal titanium implants are now most commonly used for replacement of single teeth and partial and full dentition. The success rates reported for osseointegrated implants depend on the type of implant and the criteria of success. Results are better for the mandible than the maxilla. Patient selection, careful planning of surgical and prosthetic treatment, and atraumatic, aseptic surgical procedures are essential for successful results. This article reviews various implant methods used in our Department and gives examples of treatment in particular clinical situations.

Adult↗
PubMed1990

Bone response to hydroxyapatite particles of different shapes in rabbit tibia.

Four holes drilled in rabbit tibia were filled with different commercial hydroxyapatite products. All particles caused a mild inflammatory reaction, which disappeared in 2 months. The line between the new and original bone was visible even after 6 months. No differences in healing pattern were discovered for the various products. When bone cavities are filled with hydroxyapatite particles, the shape of the particles does not seem to affect the healing process.

Animals↗
PubMed1990

Absorption of UVA light by latex and vinyl gloves.

UVA-radiation can produce malignant changes in skin. When making light cured dental fillings, dentist and dental assistant, particularly on their fingers, may be exposed to UVA radiation. The latex examination gloves were able to absorb 76% of the radiation, whereas the vinyl examination gloves absorbed only 33% of the radiation. Latex gloves thus proved to give more effective protection against UVA radiation than vinyl gloves.

Absorption↗
PubMed1990

Comparison of the minimal phototoxic dose in topical 4,5', 8-trimethylpsoralen PUVA treatment of caucasian skin and of oral mucous membrane.

The minimal phototoxic dose values for UVA radiation of psoralen-treated skin and of oral mucous membrane were studied in 16 healthy volunteers. A commercial 0.01% trioxalen ointment was used as the topical photosensitizer. In all 16 persons the radiation dose needed to induce erythema was greater for the buccal mucosa than for the skin, and the average buccal minimal phototoxic dose was 2.3-fold that of the cutaneous minimal phototoxic dose.

Administration, Topical↗
PubMed1989

A clinical trial of PUVA treatment in oral lichen planus.

Seventeen patients with histologically confirmed oral lichen planus (LP) unresponsive to previous treatments were enrolled in a study on the feasibility of photochemotherapy in the treatment of oral LP. An Espe Uviolite apparatus originally designed for irradiation of light-cured dental composite fillings was used as the source of radiation. The wavelength range of the apparatus was 320-400 (UVA) nm. Two hours before irradiation, 8-methoxy-psoralen (0.6 mg/kg) was administered orally, treatments being given at intervals of 2-3 days. Subjective symptoms disappeared totally in 13 of 17 patients at a mean cumulative dose of 6.1 J/cm2. Two months after treatment with a mean total dose of 11.6 J/cm2, 12 of the 17 lesions had markedly improved. After 12-24 months of follow-up, complete clinical remission was found in 5 of the 17 patients, 7 patients were in partial remission and 5 remained only slightly improved. We conclude that PUVA treatment may be useful for treating recalcitrant oral LP but, until more extensive studies are performed, it must be considered as experimental.

Adult↗
PubMed1988

The mylohyoid nerve and mandibular anesthesia.

Voluntary dental students received 1 injection of 1,8 ml 3% Prilocain-fenylpressin. The injection was directed beneath the mylohyoid muscle immediately behind the distal root of the first molar in order to achieve anesthesia of the mylohyoid nerve. A partial anesthesia was achieved in 21% of the subjects. In those cases, the mylohyoid nerve is, in addition to its motor innervation, also sensory to first mandibular molar.

Adult↗
PubMed1986

Apparatus for simulating extraction forces.

The extraction forces can be stimulated using a mean value indicator, extraction forceps and a phantom skull. The rocking and twisting moments occurring during "extraction" can be measured with strain gauges. Before beginning practical work on patients, dental students carried out simulated extractions of various teeth. The moments were significantly lower than forces needed for real extractions. When using the simulator, the students must be supervised by a teacher able to demonstrate the correct grips of forceps handles and the correct style in extraction.

Education, Dental↗
PubMed1985

Skeletal changes in dentists and farmers in Finland.

Two groups were studied: dentists and farmers from the Turku area. Radiologic examination of both groups included the spinal column, rib cage and shoulder joint. Spondylosis of the cervical spine was present in 68 (52.1%) of the dentists and 59 (19.2%) of the farmers. Lumbar spondylosis was more common among farmers than among dentists in the corresponding age group. Changes in the shoulder joint occurred significantly more often in dentists than in farmers. The findings in this study indicate that dentists appear to belong to the group doing heavy work.

Adult↗
PubMed1985

The influence of a free periosteal transplant on bone healing in the irradiated tibia. A radiological histological and biochemical study on rabbits.

The influence of periosteal transplants on irradiated bone cavities was studied in ten adult rabbit hind legs. The left hind legs were irradiated with a single X-ray dose of 20 Gy one week before operation. The right hind leg was used as a control. Radiological, histological and biochemical findings were recorded for specimens obtained 8 and 12 weeks after operation. Non-irradiated periosteal transplants on irradiated bone cavities induced more rapid and intense mature bone formation than irradiated periosteal transplants on the same areas. Ossification of bone cavities occurred even more rapidly, when neither the bone nor the transplant had been irradiated. These results indicate that a free periosteal transplant enhances ossification on irradiated bone cavities, whereas ossification may be inhibited or delayed after radiation therapy. A similar effect on diseased human mandibular bone has been observed in our clinical trials.

Alkaline Phosphatase↗
PubMed1984

Continuing education: attitudes and activities of Finnish dentists.

To improve the continuing education system, a group of dentists who had made little use of continuing education courses offered by the Finnish Dental Society was identified, and their opinions were mapped out and compared with those of dentists who had taken part in the systematic continuing education program. A pretested questionnaire was sent to these respective groups of 725 and 533 dentists, giving 82% and 72% return rates. A fifth of the dentists in service had never made use of the continuing education courses. Compared with all working 30-65-year-old dentists, male dentists, dentists under 35, and dentists working in rural area were over-represented in the group that had taken little part in continuing education. The dentists who had participated in systematic continuing education had also taken part in education organized by others twice as frequently as the control group. Both survey groups reported that they regularly read two professional periodicals on the average. There were only minor differences in the answers of the two groups as to whether they would be interested in participating in courses free of charge. The need for continuing education in orthodontics dominated among employed dentists, whereas self-employed dentists most frequently perceived a need in prosthodontics. Continuing education was generally considered necessary and useful but somewhat expensive.

Adult↗
PubMed1983

Penetration of 27- and 30-gauge dental needles.

Two types of disposable injection needles were tested clinically for pain of insertion, and penetration resistance. The 30-gauge needle required significantly less force (69 mN) than the 27-gauge needle (139 mN). The difference in pain perception was less remarkable. The author advises that a 30-gauge needle be used in any infiltration injection.

Disposable Equipment↗