In earlier studies, a sella turcica bridge was stated to occur in 1.75 to 6 per cent of the population. The occurrence of a sella turcica bridge has not previously been studied in a group of patients with craniofacial deviations treated by surgery. Profile radiographs from 177 individuals who had undergone combined orthodontic and surgical treatment at the Copenhagen School of Dentistry were studied. A sella turcica bridge was registered in those subjects where the radiograph revealed a continuous band of bony tissue from the anterior cranial fossa to the posterior cranial fossa across the sella turcica. Two types of sella turcica bridge were identified. A sella turcica bridge occurred in 18.6 per cent of the subjects.

The purpose of this study was to examine the association between the number of congenitally missing permanent teeth, excluding third molars, and the craniofacial morphology. The sample comprised 118 children with five or more congenitally missing teeth. Twenty-seven reference points were digitized from lateral cephalometric radiographs and 13 angular measurements of craniofacial morphology were calculated. After an initial analysis, the sample was divided into two subsamples, one with 5-12 missing teeth and the other with 13-21 missing teeth. Within each subsample there was no significant association between number of missing teeth and the angular variables, but a comparison between the two subsamples showed significantly smaller mandibular plane inclination (NSL/ML, NL/ML) and gonial angle (RL/ML), and a more prognathic mandible (s-n-pg) in the subsample with more than 12 teeth missing. It is suggested that the difference in morphology could be due to a reduced vertical development of the lower face, caused by a reduced occlusal support in the subsample with more than 12 congenitally missing teeth.

The present study focuses on orthodontically provoked, excessive root resorption. The purpose was to identify in these cases common morphological features in radiographic diagnostic material taken before treatment. The material was submitted by 35 Danish orthodontists. The goal was to improve the future orthodontic diagnostics of the dentition in order to prevent severe root resorption during treatment. The study indicates that: (1) there is a strong connection between various dental morphological characteristics, such as invagination, length of root, and root shapes, especially taurodontism, and the tendency to root resorption during orthodontic treatment; (2) there is a connection between anomalies in the dentition, particularly ectopia and agenesis, and the tendency to root resorption during orthodontic treatment; (3) there seems to be a connection between the pattern of resorption in the primary dentition and the tendency to root resorption in the permanent dentition following orthodontic treatment; (4) girls are more susceptible to root resorption during orthodontic treatment than boys; (5) one ought to be on the lookout for connections between condylar changes, root resorptions, and anterior open bites in connection with orthodontic treatment. The observation regarding root resorption in dentitions in which invaginations and taurodontic root shapes occur has not previously been reported. Also, the findings of deviant resorption patterns in both the primary and permanent dentitions in a considerable number of patients are new observations, which ought to be incorporated into orthodontic treatment planning.

The purpose of this study was to describe the prenatal formation of the human mandibular canal. Since bony canals develop in prenatal life around the nerve paths, it was assumed that the canal pattern could reflect the pattern of innervation of the dentition. Mapping of this early canal pattern does not appear to have been undertaken before. The material consisted of anthropological mandibles from the National Institute of Anthropology and History, Mexico City. A total of 302 human hemimandibles from the latter half of the prenatal period was investigated. The length, measured from the mental symphysis to the mandibular condyle, ranged from 28 to 60 mm. The dento-alveolar maturity was classified in two stages according to the appearance of alveolar sockets of deciduous and first permanent molars. The mandibles were radiographed with guttapercha points inserted into the canal openings (foramina) on the lingual surfaces of the mandibular rami. The study showed that the canal to the incisors appeared first, followed by the canal to the primary molars, and last by the one or more canals to the first permanent molars. In the most mature group, three different canals always occurred in each hemimandible. The canals were directed from the lingual surface of the mandibular ramus toward the different tooth groups. The inferior alveolar nerve presumably occurs in the mandible as three individual nerve paths originating at different stages of development. It is suggested that rapid prenatal growth and remodeling in the ramus region result in a gradual coalescence of the canal entrances that is obvious at birth. It is hypothesized that the pattern of tooth agenesis within the three groups of teeth is related to the three separate paths of innervation of the dentition.

SUMMARY The present study describes the cervical column as related to head posture, cranial base, and mandibular condylar hypoplasia. Two groups were included in the study. The ' normal ' sample comprised 21 subjects, 15 females aged 23 -40 years (mean 29.2 years), and six males aged 25 -44 years (mean 32.8 years) with neutral occlusion and normal craniofacial morphology. The condylar hypoplasia group comprised the lateral profi le radiographs of 11 patients, eight females, and three males, aged 12 -38 years (mean 21.6 years). For each individual, a profi le radiograph was taken to perform a visual assessment of the morphology of the cervical column. For the normal group only, the profi le radiographs were taken in the standardized head posture to measure the head posture and the cranial base angle.Cervical column: Morphological deviations of the cervical column occurred signifi cantly more often in the subjects with condylar hypoplasia compared with the normal group ( P < 0.05 and P < 0.01, respectively). The pattern of morphological deviations was signifi cantly more severe in the subjects with condylar hypoplasia compared with the normal group ( P < 0.01).Cervical column related to head posture and cranial base: The cervicohorizontal and cranial base angles were statistically larger in females than in males ( P < 0.05 and P < 0.01, respectively). No statistically signifi cant age differences were found. Only in females was the cervical lordosis angle (OPT/CVT, P < 0.01), the inclination of the upper cervical spine (OPT/HOR, P < 0.05), and the cranial base angle (n -s -ba, P < 0.05) signifi cantly positively correlated with fusion of the cervical column. These associations were not due to the effect of age.