Maxillary Molar Region Research Articles

Vertical control as an important ingredient in the treatment of severe sagittal discrepancies

The control of vertical development, in particular in the maxillary molar region, has often been suggested as a method of implementing sagittal change in treatment of Class II skeletal discrepancies. A group of twenty-eight Italian children in the early mixed-dentitional stage, with increased overjet and distal molar relationship, were treated orthodontically with a combination of a removable maxillary splint and high-pull extraoral traction. While only slight dorsal repositioning of the maxilla could be observed, an effective retardation of the vertical maxillary development was recorded, as well as a pronounced forward displacement of the mandibular symphysis. Distal movement of the maxillary dentition contributed likewise to the elimination of overjet observed clinically. The center of mandibular rotation was evaluated for each patient and displayed a pronounced variation illustrating different responses to the same type of appliance by different patients. The clinical implications of the above findings are discussed, and the necessity for constant appraisal of results during treatment is stressed.

Central neurilemmoma of the maxilla: Report of a case and review of the literature

Central osseous neurilemmoma is an unusual neoplasm of the jaws. The mandible is the more common bone affected in the 27 cases of neurilemmoma of the jaws which have been reported. Only one previous case has been described in the maxilla. The present case shows the classical features of central neurilemmoma and is the first case reported in the maxillary molar region.

3 才児における Streptococcus mutans, 齲蝕および歯苔の相関について

A study was made on some oral facters considered to be related to incidences of dental caries with three-year-old children in nursery school as the subjects. Positive correlation existed between the number of decayed teeth, the percentage of Streptococcus mutans to the total Streptococci in the dental plaque on the buccal side of the maxillary molar region, and Cariostat test. The plaque index for the labial side of the maxillary anterior teeth region did not show any correlation with the number of decayed teeth, the percentage of S. mutans to the total Streptococci in the dental plaque on the buccal side of the maxillary molar region, or Cariostat test. This plaque index proved to be inappropriate as an index for the oral environment. No correlation was either observed between dmft and the preference patterns for five varieties of snack. However, a strong preference for chocolate was observed in the group with a higher percentage of S. mutans to the total Streptococci in the dental plaque on the buccal side of the maxillary molar region. The group with Cariostat 2+ also showed a particular preference for chocolate.

Long-term follow-up and evaluation of transplantation of fully developed teeth

Five cases of transplantation of fully developed third molars to second or first molar sites have been reported. Three of the transplants were in the mandibular molar region and two were in the maxillary molar region. There has been long-term follow-up and evaluation of the patients in these cases up to 13 years postoperatively. None of the patients had any complaint about the transplanted tooth at the long-term follow-up visit. In all five cases, at the long-term follow-up visit, the periodontal tissues were in excellent condition and there was growth of new attachment, as demonstrated by lamina dura and periodontal membrane space in the follow-up radiographs, deposition of secondary calcification of varying amounts within the root canals and pulp chamber, and regeneration of bone in the periapical and lateral areas. There was very little, if any, resorption demonstrated in any of these five cases. The ages of patients ranged from 17 to 23 years at the time of transplantation. Regeneration of the buccal plate was demonstrated by photographs in one of the two cases where there was surgical exposure of the region of the buccal plate at a postoperative follow-up visit.

Fourth Molar in Mandible

Supernumerary teeth develop rarely in the mandibular molar region compared to the maxillary molar region and are apt to be impacted. Therefore the role of roentgenographic examination is important. Having encountered 4 cases with such teeth in the mandible (the socalled fourth molars) we would like to report on the outline of these cases, their x-ray findings and discuss the Japanese literature dealing with supernumerary teeth in the maxillary and mandibular molar region.

Distal oxidative metabolic responses induced by epidermal injury

Gingival wounds were created at the left maxillary molar region in young rats. Following injury, contralateral and gingival wound specimens were removed over a 7 day experimental period. Distal (contralateral) and wound gingival oxidative metabolism was activated within two days' after injury. Cytochrome oxidase (mitochondrial), NADH cytochrome c reductase (mitochondrial, microsomal) and NADPH cytochrome c reductase (soluble) activities were significantly greater at the distal site two days after injury than at the control sham site. Similar trends were also noted at the wound site at the same time intervals. The enzymatic activities returned to normal levels between the (2‐3) days postoperatively at the distal site and between (2‐5) days postoperatively at the wound site.

Morphogenetic response to activator treatment

E xperiments on growing primates have demonstrated that changes induced in the posture of the mandible may cause dental malocclusion.7 Class II, Division 1 malocclusions have been produced by lowering the postural position of the mandible relative to the maxilla which, in turn, caused extrusion of maxillary buccal teeth. In similar experiments, in which no extrusion of the maxillary buccal teeth was allowed, a lowering of the mandible did not result in a Class II malocclusion. The findings from these experiments indicate that the relative eruption of the posterior teeth is an important factor in the establishment of molar relationships. These results constitute the basis of the present clinical study. The purpose of this investigation was to change a Class II molar relationship into neutral occlusion by reversing the effects demonstrated in the primate experiments. This was achieved by impeding the vertical development in the maxillary molar region and concurrently stimulating vertical development in the mandibular molar segments. Correction of a Class II molar relationship by nightly use of a removable orthodontic appliance is a generally accepted procedure.1-41 6p * However, the design of the appliance has been as varied as the interpretation of its effects. For the present experiment, a removable appliance, which was a modification of the conventional activator, was designed. Theoretically, this appliance cquld elicit a series of morphogenetic responses which might contribute to the correction of the Class II malocclusion. Five hypotheses were formulated which, singly or in combination, might explain the structural changes in the transformation from a Class II to a Class I dental occlusion :

Surgical crown and bridge prosthodontics

A bilateral mandibular alveolectomy and the reduction in the gingivo-occlusal height of the opposing maxillary posterior teeth proved to be the solution for the problems associated with this case. However, such a treatment plan is not advocated for the vast majority of patients with similar situations. Before proceeding with any plan for the removal of mandibular bone, extreme caution should be exercised. This treatment was undertaken for this patient for the following reasons: 1. The patient's age was favorable. Neither a younger nor older patient would have been as favorable. 2. The alveolar bone present was in excellent condition presenting well-formed and well-positioned ridges. 3. There was no loss of normal vertical dimension. 4. Mandibular posterior soft tissues and alveolar bone were being traumatized, and would be lost in some degree under such conditions. 5. Careful examination of the roentgenographs and illustrations will reveal that the maxillary molar teeth were not extruded or elongated. If extrusion had occurred, the clinical crowns of these teeth would have been increased gingivo-occlusally with the resulting exposure of the necks of the teeth. Clinical examination failed to reveal any extrusion, but rather, it disclosed the fact that all the tissues in the entire maxillary molar regions had dropped en masse. Such a condition makes the reshaping of these maxillary teeth easier and more tolerable for the patient.