The mucosal attachment at different abutments. An experimental study in dogs.

The present experiment was performed to examine if the material used in the abutment part of an implant system influenced the quality of the mucosal barrier that formed following implant installation. 5 beagle dogs were included in the study. The mandibular premolars and the 1st, 2nd and 3rd maxillary premolars were extracted. Three fixtures of the Brånemark System were installed in each mandibular quadrant (a total of 6 fixtures per animal). Abutment connection was performed after 3 months of healing. In each dog the following types of abutments were used: 2 "control abutments" (c.p. titanium), 2 "ceramic abutments" (highly sintered Al2O3), 1 "gold abutment", and 1 "short titanium abutment". This "short titanium abutment" was provided with an outer structure made of dental porcelain fused to gold. Following abutment connection a plaque control program was initiated and maintained for 6 months. The animals were sacrificed and perfused with a fixative. The mandibles were removed and each implant region was dissected, demineralized in EDTA and embedded in EPON. Semithin sections representing the mesial, distal, buccal and lingual aspects of the peri-implant tissues were produced and subjected to histological examination. The findings from the analysis demonstrated that the material used in the abutment portion of the implant influenced the location and the quality of the attachment that occurred between the periimplant mucosa and the implant. Abutments made of c.p. titanium or ceramic allowed the formation of a mucosal attachment which included one epithelial and one connective tissue portion that were about 2 mm and 1-1.5 mm high, respectively. At sites where abutments made of gold alloy or dental porcelain were used, no proper attachment formed at the abutment level, but the soft tissue margin receded and bone resorption occurred. The abutment fixture junction was hereby occasionally exposed and the mucosal barrier became established to the fixture portion of the implant. It was suggested that the observed differences were the result of varying adhesive properties of the materials studied or by variations in their resistance to corrosion.

Comparison of the effect of the linseed extract Salinum and a methyl cellulose preparation on the symptoms of dry mouth.

The effect of a linseed extract Salinum and a sodium carboxymethyl cellulose preparation called MAS-84 was compared with regard to its effect on the symptoms of dry mouth. Twenty patients with xerostomia, who had been treated for cancer in the head and neck by radiation were recruited from the clinic for maxillofacial surgery, Malmo University Hospital. Following radiation treatment the salivation was severely reduced. The symptoms of a general feeling of a dry mouth, difficulties in chewing and swallowing, taste disturbances, problems with speech and mouth burning were registered on a subjective verbal rating scale. In addition plaque index and gingival bleeding were determined. The study design was crossover and performed single blind. The experimental period was 7 weeks. The patients were randomly divided into 2 groups. One group used Salinum and the other MAS-84 for 3 weeks. The fourth week was a wash out period and for the next three weeks the patients shifted preparation. Each of the preparations was used ad libitum. Registrations of the various parameters were undertaken on days 0, 7 and 21 of the respective period. At the initial examination all patients reported considerable disturbances from mouth-dryness. These symptoms were reduced in 15 patients during the Salinum period and in 9 during the MAS-84 period. The relief was significantly more pronounced during the use of Salinum compared to that during the use of the methyl cellulose preparation. On day 21 plaque and gingival bleeding were significantly reduced during the Salinum period but not during the MAS-84 period. The results of the present study confirm those of a previous pilot study and indicate that the linseed mucilage significantly reduced the symptoms of dry mouth. This effect increased with increasing time of saliva substitute use. The linseed mucilage Salinum appeared to be a suitable saliva replacement in mouth dry patients.

The effect of Salinum on the symptoms of dry mouth: a pilot study.

The effect of a new saliva substitute, Salinum, was tested in 37 patients with severe symptoms of reduced salivation. The majority of the patients had suffered from hyposalivation and dry mouth for more than 8 years. The saliva substitute consisted of a water soluble extract of linseed. The physical properties of this extract are similar to those of the glycoproteins of the salivary secretions. The patients used the saliva substitute for a seven days period. Prior to the use of the extract the patients reported that the most severe symptoms of decreased salivation were a feeling of dryness in the mouth and burning sensations in the tongue, pharynx and oesophagus, The majority of the patients reported that the use of Salinum reduced the symptoms of hyposalivation. Great variation in effect occurred from patient to patient. Generally the patients with the most severe symptoms experienced the greatest relief of the symptoms when they used Salinum. Although of short duration the results of this pilot study indicate that an extract of linseeds may compensate for some aspects of the consequences of reduced salivation. Further studies are needed to elucidate the feasibility of the extract as saliva replacement.

Status of mercury and selenium in dental personnel: impact of amalgam work and own fillings.

Urinary mercury (U-Hg) and plasma mercury (P-Hg) levels were higher in 244 dental personnel than in 81 matched referents (U-Hg: 1.8 and 1.1 mumol/mol creatinine, respectively; p less than .001; P-Hg: 6.7 and 6.2 nmol/l, respectively; p = .03). The amalgam in the mouth influenced mercury levels in whole blood (B-Hg), plasma, and urine. The association was nonlinear: the more amalgam, the larger the relative increase in mercury levels. The number of amalgam surfaces accounted for more of the variance in blood and urine mercury levels than did the number of fillings (e.g., U-Hg: 44% and 36%, respectively). The estimated increases in mercury level with rising amalgam load were 3.0%, 2.0%, and 0.8% per filled surface for U-Hg, P-Hg, and B-Hg, respectively (p less than .0001 in all cases). The impact of occupational exposure on U-Hg in the dental personnel corresponded to approximately 19 amalgam surfaces. Ceramo metallic restorations were associated with higher (31%) U-Hg.

On direct currents and bone formation in demineralized bone transplants.

The effect of direct current on the remineralization of a bone defect was studied in the rabbit. Bone defects in the radius of both forelegs were grafted with demineralized autologous bone. On both sides platinum electrodes were placed around the graft, and one side was connected to a power source delivering 20 microA constant current during the experimental period of 28 days. The remineralization was evaluated 14 and 28 days after operation by scintigraphy and roentgenography, planimetry included. At 28 days after operation this evaluation was supplemented by autoradiography. Roentgenographically, there was no difference between the two sides. At 14 days after operation scintigraphy demonstrated a minor delay in bone formation at the electrostimulated side. Between 14 and 28 days a significant increase in activity was noticed. On both sides, autoradiograms showed areas without uptake around the wires. It was concluded that direct currents of the studied magnitude have a negative influence on the primary bone induction process but also that it seems to influence the mineralization positively later in the bone-forming process.