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.

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.

Prevalence of malocclusion and orthodontic treatment need in children and adolescents in Bogota, Colombia. An epidemiological study related to different stages of dental development.

The aim of the study was to assess the prevalence of malocclusion in a population of Bogotanian children and adolescents in terms of different degrees of severity in relation to sex and specific stages of dental development, in order to evaluate the need for orthodontic treatment in this part of Colombia. A sample of 4724 children (5-17 years of age) was randomly selected from a population that attended the Dental Health Service; none had been orthodontically treated. Based on their dental stages the subjects were grouped into deciduous, early mixed, late mixed and permanent dentition. The registrations were performed according to a method by Björk et al. (1964). The need for orthodontic treatment was evaluated according to an index used by the Swedish National Board of Health. The results showed that 88 per cent of the subjects had some type of anomaly, from mild to severe, half of them recorded as occlusal anomalies, one-third as space discrepancies, and one-fifth as dental anomalies. No clear sex differences were noted, except for maxillary overjet, spacing, tooth size (all more frequent in boys), and crowding (more frequent in girls). Occlusal anomalies and space discrepancies varied in the different dental developmental periods, as did tipped and rotated teeth. Little need for orthodontic treatment was found in 35 per cent and moderate need in 30 per cent. A great need was estimated in 20 per cent, comprising children with prenormal occlusion, maxillary overjet, or overbite (> 6 mm), posterior unilateral crossbite with midline deviation (> 2 mm), severe crowding or spacing, congenitally missing maxillary incisors, impacted maxillary canines or anterior open bite (> 3 mm in the permanent dentition). Urgent need for treatment was estimated to be 3 per cent, comprising subjects with extreme post- and pre-normal occlusion, impacted maxillary incisors or extensive aplasia.

Long-term stability of dental arch form in normal occlusion from 13 to 31 years of age.

Based on observations of longitudinal changes in dental arch dimensions, it has been stated that an individuality of arch form and an integrity of this form exists. However, longitudinal studies evaluating arch form changes have rarely been reported in the literature. The purpose of this investigation was to use a computer-assisted method for the description and analysis of maxillary and mandibular arch form in a sample of normal occlusion subjects, and to evaluate the long-term stability in dental arch form from the age of 13-31 years. The study was carried out on 30 subjects of Scandinavian origin with normal occlusion, recorded at a mean age of 13.6 years and at follow-up at 31.1 years. Arch form analysis was based on a standardized photographic procedure, digitization of morphological landmarks, and a computerized form analysis in which arch form was described using eccentricity values of conics. No specific arch form could be found to represent the sample. Age changes occurred in arch form, although with large individual variations. For the mandible, a significant change to a more rounded arch form with age was found, which in males was accompanied by a significant increase in inter-molar distance and reduction in arch depth. There was also a significant correlation between change in mandibular arch form and increased irregularity of the lower incisors. These findings of lack of stability in arch form in normal occlusion subjects, when passing from adolescence into adulthood, further question the possibility of achieving stability post-orthodontically.

Orthodontic movement in bone defects augmented with Bio-Oss. An experimental study in dogs.

OBJECTIVE: To study if it was possible to move, by orthodontic means, a tooth into an area of the jaw that had been augmented with Bio-Oss. MATERIAL AND METHODS: 5 beagle dogs were used. The 1st, 2nd, and 4th mandibular premolars on each side were removed. The defect at the left 4th premolar site was filled with a biomaterial (Bio-Oss) while the corresponding defect in the right side was left for spontaneous healing. 3 months later, an orthodontic device was inserted in each side of the mandible. The device was designed to allow distal, bodily movement of the 3rd premolars. When the experimental teeth had been moved into the extraction sites of the 4th premolars, the animals were sacrificed and biopsies of the premolar-molar regions of the mandible sampled. The tissues were prepared for histological analysis using standard procedures. In the sections, 3 zones were identified: zone A=the bone tissue within the distal portion of the previous extraction site (4th premolar), zone B=the pressure side of the 3rd premolar, zone C=the tension side of the 3rd premolar. The area occupied by mineralized bone, Bio-Oss particles and bone marrow was determined by a point counting procedure. The width of the periodontal ligament as well as the percentage of the root surface (in zone B) that exhibited resorption was determined. RESULTS: The findings demonstrated that it was possible to move a tooth into an area of an alveolar ridge that 3 months previously had been augmented with a biomaterial. It was also demonstrated that 12 months after grafting, Bio-Oss particles remained as inactive filler material in the not utilized part of zone A. The biomaterial was not present in zone C but present in small amounts in zone B. CONCLUSION: During the orthodontic tooth movement the graft material (Bio-Oss) was degraded and eliminated from the part of the alveolar ridge that was utilized for the experiment. In the non-utilized part of the ridge the biomaterial, however, remained as a seemingly inactive filler material.

Orthodontic aspects of the use of oral implants in adolescents: a 10-year follow-up study.

The aim of the present study was to evaluate the long-term effect of implants installed in different dental areas in adolescents. The sample consisted of 18 subjects with missing teeth (congenital absence or trauma). The patients were of different chronological ages (between 13 and 17 years) and of different skeletal maturation. In all subjects, the existing permanent teeth were fully erupted. In 15 patients, 29 single implants (using the Brånemark technique) were installed to replace premolars, canines, and upper incisors. In three patients with extensive aplasia, 18 implants were placed in various regions. The patients were followed during a 10-year period, the first four years annually and then every second year. Photographs, study casts, peri-apical radiographs, lateral cephalograms, and body height measurements were recorded at each control. The results show that dental implants are a good treatment option for replacing missing teeth in adolescents, provided that the subject's dental and skeletal development is complete. However, different problems are related to the premolar and the incisor regions, which have to be considered in the total treatment planning. Disadvantages may be related to the upper incisor region, especially for lateral incisors, due to slight continuous eruption of adjacent teeth and craniofacial changes post-adolescence. Periodontal problems may arise, with marginal bone loss around the adjacent teeth and bone loss buccally to the implants. The shorter the distance between the implant and the adjacent teeth, the larger the reduction of marginal bone level. Before placement of the implant sufficient space must be gained in the implant area, and the adjacent teeth uprighted and paralleled, even in the apical area, using non-intrusive movements. In the premolar area, excess space is needed, not only in the mesio-distal, but above all in the bucco-lingual direction. Thus, an infraoccluded lower deciduous molar should be extracted shortly before placement of the implant to avoid reduction of the bucco-lingual bone volume. Oral rehabilitation with implant-supported prosthetic constructions seems to be a good alternative in adolescents with extensive aplasia, provided that craniofacial growth has ceased or is almost complete.

Single implants in the upper incisor region and their relationship to the adjacent teeth. An 8-year follow-up study.

The aim of the study was to find out if implant-supported crowns in the upper incisor region run the risk of coming into an infraoccluded position later in life. Ten adolescents with 15 implant-supported crowns were included in the study. The age of the patients at the implant surgery ranged between 14 and 19 years. They were followed up during an 8-year period. No implant loss was observed. A good or acceptable aesthetic appearance at the last observation was found in most subjects. In some of them a change in the vertical position of the implant-supported crown, resulting in infraocclusion, could be registered, especially in subjects with no incisor contact. Throughout the follow-up period, only minor loss of marginal bone support was observed at the implants. At the teeth adjacent to the implant, a reduction of the marginal bone level was observed in some patients. Of importance to consider in single implant therapy is that a fixed chronological age is no guidance for implant placement, due to a slight continuous eruption of the adjacent teeth post adolescence. An orthodontic treatment should be performed not only in order to gain space in the implant area, but also to attain good incisor stability to reduce the risk of infraocclusion of the implant-supported crown. Furthermore, 3 cases will exemplify that infraocclusion also may occur in patients who had received single implants at adult ages.

Breathing obstruction in relation to craniofacial and dental arch morphology in 4-year-old children.

The prevalence of breathing obstruction was determined in a cohort of 4-year-old children. Craniofacial morphology was studied in obstructed children and compared with data from a control group of 4-year-old children with ideal occlusion. Dental arch morphology was compared in obstructed and non-obstructed children in the group. Parents of 95.5 per cent of the study base of 644 children answered a questionnaire concerning their child's nocturnal behaviour and related questions. The 48 children who, based on parental report, snored every night or stopped breathing when snoring (the 'snoring group'), showed a higher rate of disturbed sleep, mouth-breathing, and a history of throat infections as compared with the rest of the cohort. These children were examined by both an orthodontist and an otorhinolaryngologist and, when indicated, they were also monitored in a sleep laboratory. Twenty-eight of the children were diagnosed as having a breathing obstruction (4.3 per cent of the cohort) and six children (0.9 per cent) had sleep apnoea (mean apnoea-hypopnoea index of 17.3), using the same definition as that for adults. Cephalometric values among the obstructed children differed from those of a Swedish sample of the same age with ideal occlusion. Thy had a smaller cranial base angle and a lower ratio of posterior/anterior total face height. Small, but not significant differences were seen for NSL-ML and NL-ML. Compared with 48 asymptomatic children from the same cohort, the obstructed children had a narrower maxilla, a deeper palatal height, and a shorter lower dental arch. In addition, the prevalence of lateral crossbite was significantly higher among the obstructed children.

Effect of low masticatory function on condylar growth: a morphometric study in the rat.

The aim of this study was to estimate the influence of functional alterations on the size of the mandibular condyle and to elucidate in detail, by means of histomorphometric analysis, the effect of changing the consistency of the diet on different portions of the condylar cartilage in growing rats. Forty growing rats were randomly divided into 2 groups. One group received the normal hard diet for rats; the other group received a standardized soft diet. The experimental period was 28 days. Ten animals from each group were used for gross morphometric analysis; the other 10 animals were used for histologic analysis of the condyle. The morphometric analysis of the condylar cartilage was based on the 25th, 50th, and 75th percentiles of the mediolateral sections of the condyles. The sections were divided into 3 parts: the anterior, intermediate, and posterior part; 4 measurements were performed in each. Significant differences were found in the condylar length and width between the groups, the soft diet group having a smaller condyle. The histomorphometric analysis of cartilage thickness showed significant differences between the 2 groups, being thinner in the anterior part and thicker in the posterior part of the condyle in the soft diet group. These routine histologic findings cannot explain the gross morphologic differences in the condylar size between the groups; this means that increased condylar cartilage thickness is not necessarily evidence of increased condylar growth. The results from this study indicate that a low masticatory function leads to decreased growth of the condyle and changes in the thickness of the cartilage. This may be the effect of an alteration in the stress distribution in the temporomandibular joint area, because of the absence of large masticatory forces.

Use of glass-ionomers for bracket bonding--an ex vivo study evaluating a testing device for in vivo purposes.

Seven glass-ionomer cements were tested and compared with a composite resin in order to find the glass-ionomer cement with the highest bond strength to enamel with normal anatomy and composition (not ground). Five types of surface treatment were used. The results show that Aqua Cem and Ketac Cem, both water-hardening, present the highest bond strength, followed by the conventional glass-ionomer cement Fuji IIF. Surface treatment according to the manufacturers' instructions and surface treatment with polyacrylic acid were found to give rise to the highest bond strength for all of the seven cements. However, none of the glass-ionomer cements reached the values for the composite resin Concise. The testing instrument designed for ex vivo purposes measured with high precision and accuracy and with a low methodological error.

Mutans streptococci and incipient caries adjacent to glass ionomer cement or resin-based composite in orthodontics.

Levels of mutans streptococci in plaque adjacent to orthodontic brackets retained with a glass ionomer cement (GIC) (Ketac-Cem) and a resin-based composite (CR) (Concise) were investigated, using the split mouth technique in 11 patients who, before treatment, had more than 10(5) CFU of these microorganisms. After full-term orthodontic treatment (mean 9.5 months), the percentage of mutans streptococci of total CFU count in plaque was lower adjacent to GIC-retained brackets (mean 3.9) than adjacent to CR-retained brackets (6.7), but the difference was not statistically significant. Two subjects harbored S. sobrinus. These subjects were the only ones who developed incipient caries during the orthodontic treatment. Incipient lesion formation occurred only adjacent to CR-retained brackets. This suggests that in patients who have relatively high salivary levels of mutans streptococci before treatment and especially in those who harbor S. sobrinus, the use of GIC for bonding may prevent incipient caries formation during orthodontic treatment.

Tissue characteristics of root resorption areas in transplanted maxillary canines.

The aim of the present study was to describe some histopathologic features of tissues collected from root resorption areas of maxillary canines after transalveolar transplantation surgery. In 8 of 101 transplanted canines, complications including cervical root resorption occurred between 6 and 11 years after treatment. The resorptive processes were located at the supra-alveolar portions of the distal and/or mesial aspects of the teeth and were scheduled for treatment involving surgical exploration. The resorption cavities, which extended from the cementoenamel junction to a position immediately below the bone crest, were filled with a granulation tissue. In four of the diagnosed complication cases, this granulation tissue was carefully excised concomitant with the adjacent gingival tissue after flap elevation and placed in a buffered fixative. After proper soft-tissue healing, the cavities were filled with a glass-ionomer material. The collected biopsy specimens were, after fixation and, in one case, decalcification in ethylenediaminetetraacetic acid, dehydrated and embedded in Epon. Sections 3 microns thick were produced, stained in periodic acid-Schiff and toluidine blue, and used for histometric and morphometric analyses. The histologic analysis showed that the dissected tissue harbored well-encapsulated areas of inflammatory infiltrates. The lesions comprised a relatively low volume of collagen and a large number of inflammatory cells, predominantly lymphocytes.

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.

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.

Dentofacial growth in orthodontically treated and untreated children with juvenile chronic arthritis (JCA). A comparison with Angle Class II division 1 subjects.

The changes in craniofacial growth and development of dental occlusion were studied in children with juvenile chronic arthritis (JCA), and treatment with functional orthodontic appliances (activators) was tested in both JCA and healthy children with distal occlusion. Fifteen JCA children with Angle Class I occlusion and 15 JCA children with Angle Class II malocclusion were followed longitudinally and compared with 23 healthy children with Angle Class II malocclusion. The facial growth of the JCA children without need of orthodontic treatment mainly followed the normal pattern while the JCA children with Angle Class II malocclusion had a deviating facial morphology, which became more abnormal during growth. During the orthodontic treatment period a slight improvement was seen in mandibular positions in the sagittal and vertical planes in both treated groups, but the changes were more marked in the healthy children. None of the treated groups attained completely normal facial morphology, but in most children the occlusion improved and could be classified as normal. The morphology achieved by treatment largely remained the same during the follow-up period and relapse was seen only in a few children. JCA children with minor skeletal discrepancies can be satisfactorily treated during growth with functional orthodontic appliances, possibly in combination with fixed appliances. Even if skeletal changes in response to orthodontic treatment are rather limited, these changes combined with the improvement in dental occlusion obtained through treatment may result in better dentofacial aesthetics. Furthermore, jaw functions are likely to improve which also might benefit the patient from a psychosocial point of view.

[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.

Craniofacial structure in children with juvenile chronic arthritis (JCA) compared with healthy children with ideal or postnormal occlusion.

The aim of the present study was to evaluate the influence of condylar destruction on the craniofacial growth of children with juvenile chronic arthritis (JCA) and to compare their craniofacial structure with that of healthy children with ideal or postnormal occlusion. Thirty-five children (7 to 16 years) affected by JCA were compared with 136 children (7 to 16 years) with normal facial structure and occlusion (ideal group) and 62 children (7 to 12 years) with postnormal occlusion (postnormal group). Panoramic radiographs and lateral cephalograms were taken to detect condylar lesions and analyze facial structure. Multiple regression analysis was applied to test the possible relationships between the groups. The present study largely confirms earlier findings that the JCA group has a characteristic craniofacial structure. Their structure differed not only from the facial characteristics of children with ideal, but also to some extent, from children with postnormal occlusion. Furthermore, the craniofacial structure of children with JCA varied greatly, and radiographs showed that the most extreme craniofacial changes, particularly the mandibular structure, were associated with condylar lesions. In conclusion, the arthritic condylar lesions seem to be the main etiologic reason for the altered facial structure and changes in the occlusion in children with JCA. Influences of other factors, such as masticatory muscular function, are also discussed.

Osseointegrated implants as orthodontic anchorage in the treatment of partially edentulous adult patients.

In nine partially edentulous adult patients, mean age 47 years (range 17-64 years) 23 osseointegrated implants were used as orthodontic anchorage to perform the following types of orthodontic tooth movements: tipping, torquing, rotation, intrusion, extrusion, and those associated with bodily movements. The total orthodontic treatment period varied between 4 and 33 months (x = 17 months). Pre-operatively, at the start and end of orthodontic treatment, and at the annual controls, clinical as well as biometric and radiographic (panoramic, lateral cephalograms and periapical radiographs) recordings were performed. The osseointegrated anchorage units were used as reference points for measurements of two- and three-dimensional tooth movements with a co-ordinate machine. The 2-D tooth movements varied between 0.2 and 6.2 mm, whereas movements in the third dimension, extrusion and intrusion, ranged from 0.0 to 13.5 mm. The movement in space for the individual tooth was observed to be, as a mean, 3.9 mm (range 0.6-18.7 mm). However, the osseointegrated titanium implants (fixtures) used as orthodontic anchorage remained in position when orthodontically loaded for the various tooth movements. After completion of the orthodontic treatment the fixtures served as abutments for permanent prosthetic constructions.