Orthodontic space closure versus implant placement in subjects with missing teeth.

The aim was to give a systematic review of alternative orthodontic space closure and implant placement in young adults with missing teeth. A literary search was made in the MEDLINE (Pub Med) database from 1990 to 2007. Totally 146 articles were found. Only studies in the English language or other languages with an English abstract were accepted, which reduced the number to 91 articles. Among them, only one prospective and three retrospective articles, two review papers and five case reports with discussion were found. The others presented one or two cases, or focused on treatment planning of missing teeth in general. Consequently, they were excluded. Moreover, a manual search of bibliographies in relevant journals gave no additional information. Thus, only 11 relevant articles were accepted. This systematic review clearly showed, that both alternatives (space closure or implant placement) present advantages as well as disadvantages. Knowledge about tissue reaction of orthodontic space closure and dento-facial development (including continuous changes of the dentition and its supporting tissues) are significant factors in the choice of treatment. Thus, we need more research on basic level and clinical follow-up studies of large samples.

Implants and/or teeth: consensus statements and recommendations.

In August 23-25, 2007, the Scandinavian Society for Prosthetic Dentistry in collaboration with the Danish Society of Oral Implantology arranged a consensus conference on the topic 'Implants and/or teeth'. It was preceded by a workshop in which eight focused questions were raised and answered in eight review articles using a systematic approach. Twenty-eight academicians and clinicians discussed the eight review papers with the purpose to reach consensus on questions relevant for the topic. At the conference the consensus statements were presented as well as lectures based on the review articles. In this article the methods used at the consensus workshop are briefly described followed by the statements with comments.

Histochemical analysis of masticatory muscle in the growing rat after prolonged alteration in the consistency of the diet.

Changes in muscle function induce alteration in craniofacial bone growth. To study morphological changes after alteration of masticatory function, NADH-TR reductase and myofibrillar Ca2+-activated ATPase were assessed histochemically, after alkaline and acid pre-incubation, in sections from the anterior deep masseter and the anterior digastric muscles. Type IIA, IIB and transitional fibres of the anterior deep masseter but not of the digastric muscle were smaller in a soft-diet group than in a normal-diet group. There was a small percentage of type IIA fibres and a large percentage of type IIB fibres in the anterior deep masseter in the soft-diet than in the normal-diet group. The elevator muscles do not encounter the same functional demands on a soft as on a normal diet, and this causes different biting and chewing loads, which may in turn induce skeletal changes.

Prevalence and awareness of malocclusion in Swedish men.

Previous orthodontic treatment, the awareness of malocclusion, the demand for orthodontic treatment and the prevalence of malocclusion were studied in 389 Swedish men, aged 21-54 years (mean age 32 years). Nine percent had been treated with an orthodontic appliance and 15% reported that permanent teeth had been extracted on orthodontic indications. Malposition of teeth was found in 75%, with rotation as the most common type of malposition. Crowding was recorded in 43% and spacing in 18%. Fifty-seven percent had some occlusal anomaly. The need for orthodontic treatment was rated on a four-point scale. It was found that 76% were in need of treatment. The need for treatment was only slight in half of the men but moderate to urgent in 25% of the sample. About a quarter of the men were aware of malposition of front teeth, equally often for maxillary and mandibular teeth, but only about 1% were aware of malposition of posterior teeth. Only a few percent thought they were in need of orthodontic treatment. The presence of malocclusion was correlated to age, place of birth and educational level. This might perhaps be a consequence of tooth loss.

Tooth loss, prosthetics and dental treatment habits in a group of Swedish men.

Dental history, dental status, the need for prosthetic treatment and dental treatment habits were studied in 389 men aged 21--54 years. The men were selected from a group undergoing military refresher training in the south of Sweden. One percent of the men were toothless. About 3% had full dentures in one or both jaws and an equal percentage had partial dentures. About 3% of the men had bridges in the maxilla and 2% in the mandible. Tooth loss was greatest in the mandibular molar segment, followed by the maxillary molar segment. By means of an index for dental status about 8% of the men were judged to be in great need of prosthetic treatment for aesthetic reasons and/or to improve occlusion. Age, place of birth, educational level and smoking habits were among the factors which seemed to be related to dental status. Seventy percent of the men reported that they went to the dentist once a year, while about 10% seemed rarely or never to seek dental treatment. Dental treatment habits were correlated to place of birth, number of brothers and sisters, edentulousness and the need for prosthetic treatment, among other factors.

The role of the orthodontist in the multidisciplinary approach to periodontal therapy.

The effects of orthodontic tooth movement upon the supporting tissues of teeth with periodontal breakdown are conflictingly reported. Recent studies in beagle dogs have, however, enlarged our understanding of the effects of tipping and bodily movements of teeth and of factors important in retention after orthodontic treatment. Such treatment should always be preceded by the treatment of periodontal inflammation and the elimination of deep pockets.

Infraocclusion of primary molars with aplasia of the permanent successor. A longitudinal study.

Infraocclusion of deciduous molars that also lack a permanent successor is found to progress more than where a successor is present, while exfoliation is severely retarded. The aplasia is the most important factor in treatment planning and timing.

Activity of temporal and masseter muscles in children with a lateral forced bite.

The activity of the temporal and masseter muscles with the mandible in postural position and during chewing, maximal bite in the intercuspal position, and swallowing were recorded electromyographically in nineteen children with laterally forced bite. Of the children, aged 8-12 years, sixteen had unilateral crossbite. In all of the individuals there was lateral deviation between the retruded contact position and the intercuspal position. The magnitude of the lateral deviation was measured with a modified gnathothesiometer. The muscle activity was recorded bilaterally from the temporal muscle and from the masseter muscle. In the postural position asymmetric activity was found in the temporal muscle suggesting that the mandible in postural position was still displaced to the side of forced bite. During chewing the activity was asymmetric both in the anterior and the posterior temporal portions. This asymmetric muscle activity was interpreted as an adaptation to avoid cuspal interferences. Also in maximal bite the muscle activity was asymmetric, while the activity during swallowing was affected less than in the other functions. The swallowing activity was, however, less in children with a forced bite than in children with normal occlusion.

Occurrence and distribution of root resorption in orthodontically moved premolars in dogs.

An experimental study in dogs, in which 15 teeth were bodily moved and 9 teeth were tipped with the same amount of horizontal force. Less resorption was found with tipping, and less was found on the mesial root surfaces moved into the extraction sites than on the furcation side of the distal roots.

Roentgencephalometric standards for the facial skeleton and soft tissue profile of Swedish children and young adults. II. Comparisons with earlier Scandinavian normative data.

The purpose of this report is to compare a Swedish so-called normal material (Thilander et al.1983) with previously presented normal materials of Scandinavian origin and with standards for parameters in some frequently used roentgencephalometric systems. The material comprises Swedish children and young adults who fulfil special criteria of normal occlusion and harmonius skeletal relations and in whom roentgencephalometric data were collected. Parts of the material here reported are designated the 10-, 13- and 16-year-old groups. Comparison of the cephalometric data for the age-group 10 years in our material and a previously presented Norwegian normal material (Humerfelt 1970) showed remarkably good agreement for both angular and linear measurements in both sexes. Good agreement was also found between angular measurements in the 16-year-old group and those presented by Werner(1954) for Swedish 13-16-year-old children, but there seem to be differences for certain mandibular parameters. Comparison with data for 12-year-old Swedish boys with varying occlusion, presented by Björk(1947), reveals differences for several angular mandibular measurements. The highly significant differences between the linear measurements in the two materials are probably partly explained by age differences but also tend to corroborate the indications of differences in skeletal pattern suggested by the angular measurements, which are due to the selection criteria. Finally, comparison with the Bergen norms for the straight face (Hasund 1973) shows that the agreement is generally acceptable for angular measurements and the standards may be considered sufficiently reliable for use in clinical orthodontics. They should be supplemental with the age-related variations, however.

Dentofacial relations in young adults with unilateral complete cleft lip and palate. A follow-up study.

A retrospective study was made on 30 patients born between 1958 and 1969 with unilateral complete cleft lip and palate (C-UCLP) and operated on at the Department of Plastic Surgery, University Hospital, Umeå, Sweden. All patients were operated on by the same surgeon. The results are based on data from records at 5, 10, 16 and 20 years of age. The facial morphology of the cleft children at 5 years of age was rather close to that of the normal children. During growth the faces became retrognathic, more visibly so in the maxilla resulting in straight or concave profiles. This was more evident among the boys. There were no differences regarding maxillary growth between children bone grafted at 10 to 16 years of age and those bone grafted after 16 years of age or not at all. Although surgical procedures and orthodontic treatment varied, 70% had less than 3 teeth in crossbite relationships at 20 years of age. An important factor to take into consideration is the fact that in addition to the influence that the cleft morphology and treatment have on the dentofacial growth, other dentofacial growth patterns also exist among the cleft patients. Generally the groups of patients reported are rather small and therefore conditions like these can have a strong influence on the results.

Infrabony pockets and reduced alveolar bone height in relation to orthodontic therapy.

Experimental animal studies have shown that orthodontic movement of teeth into infrabony pockets may be detrimental to the periodontal attachment. After elimination of subgingival plaque infection in the experimental animals, no additional loss of connective tissue attachment occurred. An experimental model has shown that a tooth with normal periodontal support can be orthodontically moved into an area of reduced bone height with maintenance of height of connective tissue attachment level and alveolar bone support. The results from these experimental studies have been tested clinically.

[Osseointegrated implants in adolescents. A three year study]. / Implantaten bij jongeren. Een driejarig onderzoek.

In 15 adolescents (age 13.2 to 19.4 years) in the late dental stage implants (n = 27) were chosen to replace missing teeth due to congenital absence or trauma. The patients were followed for at least 3 years. No fixture losses occurred. Only minor loss of bone support at the fixture was observed, while adjacent tooth surfaces showed some loss. Infra-occlusion of the implant restorations was noticed in patients with residual craniofacial growth. Thus, the dental and skeletal maturation, and not the chronological age, must be taken into account to avoid infra-occlusion. Furthermore it is important to gain enough space for the fixture in the mesio-distal direction in order to avoid the risk of marginal bone loss at teeth adjacent to the implants.

Basic mechanisms in craniofacial growth.

Bone growth is controlled by growth areas, not active growth centers as stated earlier. Conversion of cartilage, sutural deposition, and periosteal remodeling are the basic phenomena involved in growth mechanisms. The principles of bone growth will result in changes in the size and shape of the mandible and the nasomaxillary complex in the three dimensions. The growth rate varies at different times during the development of the child. The processes of facial growth and changes in the dental arches continue to a much later age than had previously been realized. Although our knowledge of craniofacial growth has increased during recent times, it is still incomplete with regard to the explanation for the regulation of craniofacial growth.

Complications of orthodontic treatment.

Orthodontic treatment may in some cases initiate damage to teeth and supporting tissues (decalcification and gingivitis) or root resorption, pulp damage, allergic reactions, or craniomandibular dysfunction. This review updates some interesting findings regarding these problems.

Transalveolar transplantation of maxillary canines. A critical evaluation of a clinical procedure.

Regular discussions between the Departments of Oral Surgery and Orthodontics at Göteborg University have resulted in a modified operative technique for impacted maxillary canines, called transalveolar transplantation. After exposure of the operation field, large amounts of bone are removed, avoiding damage to the surface of the cementum and the periodontal membrane. Throughout the surgical procedure the tooth is kept in the alveolar process and then finally gently moved to its desired position. Orthodontic fixation is used to stabilize, not to immobilize, the tooth. So far 101 maxillary canines have been autotransplanted in 85 patients (11-76 years old) with an observation period of 1-17 years. Transalveolar transplantation is considered a good alternative for impacted maxillary canines, provided that the treatment planning is discussed by an orthodontist and an oral surgeon together and the treatment is performed with meticulous surgical techniques and adequately functioning orthodontic fixation and used in patients with proper oral hygiene.