Mikko Altonen

Follow-up study of apicoectomized molars.

The present material consists of 46 respected molars, 20 of which were located in the maxilla and 26 in the mandible. Altogether, 93 different roots were resected and 109 root fillings made. The follow-up study was made 1-6 years after the apicoectomy. The patients were examined clinically, special attention being paid to the subjective and objective symptoms shown by each apicoetomized tooth. Then a stereoscopic picture of the resected tooth and an orthopantomogram were taken. Of these 46 apicoectomized teeth, 33 (71%) showed complete healing, five (11%) were uncertain, four (9%) showed unsatisfactory healing, and four (9%) were extracted. When examining molars it seems reasonable to study each root as a separate case. Among the 93 apicoectomized roots, there were 75 (81%) cases of complete healing, six (6%) of uncertain healing, four (4%) of unsatisfactory healing, and eight (9%) extractions. There was no difference between the groups of radicular cysts and periapical granulomas in healing. The percentage of cases of complete healing was higher when approximately one-half of the roots were resected than when approximately one-third were resected. The orthograde root filling made in connection with resection was found better than the retrograde or the earlier orthograde filling. It was also found that when several periapical lesions were present in the other teeth, the number of complete healings in the group of resected teeth was less.

Determination of the Gonial Angle from the Orthopantomogram

This study demonstrates that the size of the gonial angle can be determined from the orthopantomogram with the same degree of accuracy as from the generally used lateral cephalogram, the gonial angle being formed by the tangents of the lower border of the mandible and the distal border of the ascending ramus and the condyle on each side. It also shows that the right and left gonial angles can be quite easily determined individually from orthopantomograms, thus avoiding the disturbing influence of the superimposed images found on lateral cephalograms. It proves conclusively that the orthopantomogram is the more obvious choice for determination of the gonial angles.

Predicting angulational development and eruption of the lower third molar.

Abstract No Abstract Available. From the Departments of the Pedodontics, Orthodontics and Roentgenology, Institute of Dentistry, University of Helsinki.

Evaluation of autotransplantations of completely developed maxillary canines

Transplantation of 28 maxillary canines was followed up in 22 patients with an average age of 25.2 s.d. 9.9 years. The root was fully developed. The mean immobilization time was 6.6 weeks and the mean follow-up period 17.8 months. Results seemed to be better in the age group of 13--20 years than in 21--30 and 31--47 years. Statistically significant better results were found in the youngest than in the older groups in the return of vitality, vertical bone resorption, periodontal space in the lamina dura. Four of the 28 teeth were extracted because of great mobility caused by poor bone regeneration and vertical resorption of the alveolar bone: three in the middle age group and one in the oldest. Pulp extirpation was performed on nine teeth: six in the oldest group and three in the middle group. Vitality returned in only three teeth, all of which belonged to the youngest group. Root resorption was observed in all age groups; in 76% of the cases it occurred in the apical third, and was generally inflammatory. The causes of the failure of transplantation were considered to include damage of the transplant during removal from deep palatal malposition, poor regeneration of the bone around the transplant and chronic periodontal infection. The prognosis for transplantation was found to be fairly good for patients under 20 years of age but poorer for older age groups.

Developmental position of lower third molar in relation to gonial angle and lower second molar.

Abstract No Abstract Available. From Departments of Oral Surgery, Pedodontics, Orthodontics and Dental Roentgenology, Institute of Dentistry, University of Helsinki.

Treatment of zygomatic fractures: Internal wiring-antral-packing-reposition without fixation

Fifty-two patients with zygomatic fractures were examined clinically and roentgenologically 1 to 4 years after treatment. Of these patients, 15 were treated with wiring fixation, 26 with antral packing using plastic tubing, and 11 with reduction only, without fixation. In the last group, the hospital stay was the shortest. These patients had also less complications and roentgenological changes when compared with the other groups. This was considered to be due to the fact that fractures not requiring fixation are initially less difficult than fractures requiring other treatment. At clinical examination, internal wiring fixation proved to be better than antral packing when hospital stay, restoration of the function of the infra-orbital nerve, the position of the eye, symmetry of the palpebral fissure and the final cosmetic results are considered. In the antral packing group, the result was better when jaw movements and occurrence of permanent diplopia were compared. The roentgenological examination revealed that the reduction results were more exact with internal fixation than with antral packing.

Effect of two antimicrobial rinses and oral prophylaxis on preoperative degerming of saliva

Two degerming mouthrinses, a 1% povidone-iodine and a 0.2% aqueous solution of chlorhexidine gluconate, were tested with regard to their degerming effect on the saliva. The study comprised two parts. In the first part 19 dental students with good oral hygiene rinsed their mouths at weekly intervals with 10 ml of the povidone-iodine and 10 ml of the chlorhexidine solution. A control group of 12 students and nurses with healthy teeth and gums rinsed their mouths with 10 ml of plain water. In the second part 11 adult patients with periodontal disease used the two test rinses at weekly intervals both before and after periodontal prophylaxis including scaling of the teeth. Non-stimulated saliva was simpled immediately before and 5, 30, 60, and 120 min after each rinse. Part of the saliva was cultured on blood agar plates to show the growth of aerobic microbes. The remainder of the saliva was poured over a Dentocult dip-slide for determination of the number of acidophilic bacteria. The results showed that in the water control group the bacterial count increased in spite of the rinse. When compared with the prerinse values, both test rinses clearly reduced the amounts of bacteria. Chlorhexidine reduced the bacterial count 5 min after the rinse about one logarithm more than povidone-iodine, did, and the degerming effect of chlorhexidine was also of longer duration than that of the povidone-iodine solution. The periodontal prophylaxis in the adult group did not seem to lower the pre-rinse bacterial counts but did slightly improve the duration of the effect of both test solutions. The dip-slide tests showed that 28% of the subjects had no growth of acidophilic bacteria. This absence was not dependent on the other bacterial flora of the saliva. In the cases with a positive dip-slide test, the number of acidophilic bacteria decreased with both test solutions according to the pattern revealed by the blood agar plate cultures.

Transplantation of free tibial periosteal graft on alveolar bone defect in adult rabbit.

The healing of bone defect in eight adult rabbits was studied. The age range of animals was 5-23 months. The bone defects were made symmetrically in the inferior surface of the mandibles. At the defect site the root surface of continuously erupting mandibular incisors was exposed. On the left side, the bone defect was covered with a local periosteal flap (control side) and on the right side the defect was covered with a free periosteal graft from the tibia (test side). The healing of bone defects and the amount of new bone were studied. The quality of the bone formed was investigated histologically. The findings of this investigation led to the following conclusions: (1) The bone defects healed on both sides. The amount of bone on the control side was identical to that in the anatomical region. On the test side the amount of bone formed was in seven cases two to threefold that formed on the control side. (2) The histological study proved that the bone formed was lamellar bone, being identical on both the control and the test side. (3) The ages of the animals or the length of follow-up time did not affect the amount of new bone, the healing of the defect or the quality of new bone. (4) The eruption of the incisors was symmetrical. In this study the free periosteal graft from the tibia led to better bone formation than the local periosteal flap in the induced bone defects of the tooth-bearing region in the mandible of the adult rabbit.

Midface deviation due to mandibular fractures. (An experimental study with clinical comparison).

An experimental study was undertaken into the effect of fractures produced in the body of the mandible, the base of the condylar process and the mandibular condyles, on the bones of the middle third of the face using rabbit sucklings. The rabbits were sacrificed when fully grown, when it was found that in all cases the bones of the middle face had deviated to the traumatized side in comparison with the neurocranium. The greatest asymmetry occurred after injuries to the condyles and least following injuries to the body of the mandible. A comparative study on patients past growing age who had had an injury to the condyle before the age of 10 years suggested a similar disturbance of development. The present material, however, was so limited that reliable conclusions could not be drawn.

Transantral, subperiosteal resection of the palatal root of maxillary molars

A resection method for the palatal root of the maxillary molar is presented, in which the tip of the root is exposed by widening the resection opening of the buccal roots into the maxillary sinus and by lifting the periosteum from its underlying tissue above the tip of the root. The method suits cases in which the mucous membrane of the sinus is healthy and the floor of the sinus extends between the roots or the tip of the root is close to the sinus. By this method, palatal opening and damage to the mucous membrane of the sinus are avoided. Pain and discomfort are minimal. In addition, the topographic anatomy of the floor of the maxillary sinus and the dental roots and radiographic methods suitable for diagnostics are discussed.