Clinical comparison of hydroxyapatite-coated titanium dental implants placed in fresh extraction sockets and healed sites

The placement of hydroxyapatite-coated dental implants in fresh extraction sockets was compared to placement in adjacent healed sites in 14 patients. Systematic sequential documentation was obtained regarding periodontal health, radiographic bone levels, and implant stability at the time of implant placement, at uncovering, and from 8 to 24 months (mean 16 months) after loading and restoration delivery. There were no significant differences in any clinical parameter between those implants placed in fresh extraction sockets and those placed in healed areas. Periodontal health, maintenance of crestal bone levels, and implant stability were excellent for implants placed in both types of recipient sites. The results of this study suggest that hydroxyapatite-coated dental implants can be successfully placed in fresh extraction sockets utilizing otherwise standard implant placement techniques, and that they appear to clinically perform equally well in fresh sockets and healed sites.

[The significance of the gingival ligament system for orthodontic tooth movement--an experimental animal study]

In ten six-month-old Wistar rats, we studied tooth movement after fiberotomy. To trace bone remodeling, all rats received two labelling dyes in five days intervals. We found that ligament regeneration is complete after 14 days. Using fluorescence microscopy we found in rats when stretching forces were continued that a reversal of tooth drift takes place in comparison to the control side, indicating an identical behaviour as before. Only in cases with inflammation no fibre regeneration was found and the mesial drift of the neighbouring tooth was missing. Because of these side-effects this procedure seems not to be a useful adjuvant to enhance orthodontic tooth movement.

[Experimental studies on morphological changes of microvascular architecture following the free gingival autograft on denuded alveolar bone]

The purpose of the present studies was to examine the healing process following the free gingival autograft placed on the recipient bed either with or without periosteum in 54 adult mongrel dogs with healthy periodontium. A recipient bed was prepared on denuded alveolar bone in a definite portion of the attached gingiva of the right maxillary canine tooth, and the graft was taken from the attached gingiva of the left maxillary canine and transplanted in the recipient bed. Morphological changes were observed by means of vascular corrosion casts on the postoperatively 3rd, 5th, 14th, 21st, 28th, 42nd, 56th and 84th day. The healing process following the free gingival autograft on the denuded alveolar bone showed that this graft survived in its margin by recirculation from the cut margin of the recipient bed, and in its center the necrotic tissue changed to granulation tissue, which gradually cicatrized. This was different from the healing process following the free gingival autograft on periosteum, in which the graft was survived entirely by recirculation from the vascular plexus of the periosteum on the recipient bed. This may help to restore the function proper.

[Experimental study of periodontal tissue regeneration. Changes in the periodontium after tooth implantation with and without periodontal ligament]

The role of the periodontal ligament in periodontal tissue regeneration was evaluated. The materials included bilateral upper 1st premolars and lower 2nd, 3rd, and 4th premolars of 11 adult Beagle dogs, aged from 3 to 6 years. Before implantation, the right teeth were extracted and kept for a period of more than 3 months in "a solution for reserving teeth". The left teeth on the other hand, were extracted and soon implanted thus retaining the periodontal ligament into the newly created bone cavities prepared in the right edentulous areas. At the same time, the right reserved teeth were implanted into the left tooth sockets. Implanted teeth were periodically observed macroscopically, radiographically, and histologically for a 6-month period. Macroscopical observation showed good clinical repair in the bilateral sides of the tooth implantation with and without a periodontal ligament. After a 6-week experimental period, radiographic observations of the implanted lower right teeth having a periodontal ligament revealed lamina dura-like findings. Histopathological investigation revealed ankylosis and root resorption on the left side, where the reserved teeth without a periodontal ligament were implanted. But regeneration of the periodontal tissue complex, which consisted of the gingiva, alveolar bone, cementum, and periodontal ligament, was generally observed in the implanted right teeth having a periodontal ligament. These results suggest that the periodontal ligament cells play a significant role in periodontal tissue regeneration.

[Cellular competition and healing]

Different therapeutic solutions have been tried to obtain a new attachment. Several animal experiments have studied cellular colonization of radicular surfaces exposed to the disease then planed. Only the cells from the periodontal ligament seem to be able to form a new attachment. The interposition of a membrane seem to prevent gingival and osseous tissues to interfere with the periodontal ligament. The periodontal ligament cells colonize then the radicular surface.

A long-term prospective evaluation of the circumferential supracrestal fiberotomy in alleviating orthodontic relapse

This prospective study conducted during a period of nearly 15 years initially involved 320 consecutively selected cases. The primary purpose of the investigation was to statistically evaluate the efficacy of the circumferential supracrestal fiberotomy (CSF) procedure in alleviating dental relapse following orthodontic treatment. The "Irregularity Index" method of Little for measuring the malposition of teeth was used to quantitatively record the relapse of the control and CSF cases at approximately 4 to 6 years after active treatment and again at 12 to 14 years after active treatment. The differences between the mean relapses of the control and the CSF cases were highly significant at both time intervals. The surgical procedure appeared to be somewhat more effective in alleviating pure rotational relapse than in labiolingual relapse. On a long-term basis, the CSF procedure was shown to be more successful in reducing relapse in the maxillary anterior segment than in the mandibular anterior segment. Nevertheless, a significant and unpredictable variation in individual tooth movement following orthodontic treatment was observed in both the control and CSF groups. No clinically significant increase in the periodontal sulcus depth nor decrease in the labially attached gingiva of the CSF teeth was observed at 1 and 6 months following the surgical procedure.

Atraumatic suture of the mucoperiosteal flap in the transsphenoidal approach. A new technique

Fifty-three patients were operated on with the transsphenoidal approach and a biologic tissue adhesive was used, in order to fix the mucoperiosteal flap. Results and advantages of the technique are discussed.

Periodontal attachment responses to surgical injury in the cat. Removal of buccal bone with and without placement of foreign body at ligament periphery

Recently, PDL progenitor cells were claimed essential for the establishment of new connective tissue attachment to root surface. To further test new periodontal attachment after surgical injury, portions of the buccal alveolar plate were removed from the canines of 4 cats. Removal of bone was carried out with or without removal of the underlying PDL, and in half of the experimental sites, dental amalgam was placed at ligament periphery. Tissue blocks were prepared for routine histologic evaluation (H & E) and specific collagen stains (Mallory Trichrome and Mallory PATH). Exfoliation of amalgam was noted in 6 experimental sites during the healing period. At all sites, plaque accumulation and marginal gingivitis were observed before sacrifice. Histologic observation demonstrated limited new connective tissue attachment to root surfaces at PDL periphery where bone, PDL and cementum had been removed. Where PDL was retained, connective tissue attachment was present which appeared to be the result of fiber interdigitation between root-inserted fiber ends and gingival wound edge fibers. "Blockage" of PDL cell migration by amalgam could not be well controlled. However, the placement of amalgam seems to have interfered with new connective tissue attachment and/or cementogenesis. In 5 specimens, root resorption had progressed into dentin. At these sites, collagen tufts appeared to arise from dentin. These tufts were in intimate contact with zones of dense inflammatory cellular infiltrate and connective tissue elements. We suggest that this observation may be a further tissue response to injury, namely: root resorption with the unmasking of dentinal collagen, which may finally lead to fiber interdigitation.

Evaluation of different types of autotransplanted connective tissues as potential periodontal ligament substitutes. An experimental replantation study in monkeys

The purpose of the present study was to investigate connective tissue autotransplants as potential periodontal ligament substitutes. Green Vervet monkeys (Cercopithecus aethiops) were used. Maxillary permanent central incisors were extracted, root filled extraorally and the periodontal ligament removed from the root surface and the socket wall. Two circular cavities were prepared mesially and distally on the root surface. Different types of connective tissue autotransplants were then placed in these cavities, whereafter the teeth were replanted. The animals were sacrificed 8 weeks after replantation and the replanted teeth were examined histometrically. The connective tissue autotransplants were then examined for their capability of preventing root resorption or inducing or forming a new periodontal ligament, including periodontal fibers and cementum. Autotransplanted cutaneous and mucosal connective tissue as well as periosteum and fascia were all found to partially prevent ankylosis by forming a fibrous barrier between the root surface and the alveolus. However, no new cementum was formed. Periodontal ligament transplants, dental follicular tissue and possibly gingival connective tissue were the only tissues capable of both preventing ankylosis and forming a hard tissue on the surface of the cavity with a morphology similar to cementum. It is concluded that cementogenesis requires a highly specialized connective tissue. In this experiment, only odontogenic tissues had this capacity.

The effect of limited drying or removal of the periodontal ligament. Periodontal healing after replantation of mature permanent incisors in monkeys

The effect of limited drying or removal of the periodontal ligament upon periodontal healing after replantation of incisors was studied in green Vervet monkeys. All teeth were examined histologically either 2-, 4- or 8 weeks after replantation. The drying experiment demonstrated that an area of ankylosis was established after 2 weeks corresponding to the dried portion of the root and was removed by a resorptive process in the majority of cases after 8 weeks. The removal of the periodontal ligament led to development of surface-, inflammatory- and replacement resorption. Furthermore, 1 mm2 and 4 mm2 lesions on the root surface developed transient ankylosis which disappeared after 8 weeks while lesions of 9 mm2 or 16 mm2 in size resulted in an ankylosis which, in most cases, persisted after 8 weeks. Based on these findings, it is postulated that physical removal or extended drying of the periodontal ligament initiates a rapid osteogenesis in the alveolus which establishes an ankylosis. If the damaged area is placed next to a zone on the root surface with a vital periodontal ligament, a later resorptive process is established from this zone, whereby the ankylosis area is gradually resorbed. It is estimated that the extent of this process in this experiment amounted to possibly 1 -- 1.5 mm.

Subperiosteal transmucosal porous ceramic/titanium implants. Clinical experience from three cases

Porous ceramic (Al2O3) material was used in combination with titanium fixtures as subperiosteal transmucosal implants in three patients at the Department of Oral Surgery and Oral Medicine, Dental Faculty, University of Oslo. Ceramic pieces were furnished with titanium receptacles and matching threaded posts. The implantation approach was based upon two stages, the first for subperiosteal placement of the ceramic onlay segment containing the titanium receptacles, and the second procedure for perforation of the mucosa and insertion of the posts intended for prosthetic use. A healing period of 8 weeks was planned between the two procedures. In one of the patients, however, the implants were removed only a few weeks after placement because of inflammation and soft tissue breakdown over the ceramic material. Reoperation was performed, however, with the same negative results. The other two individuals retained the implants, with uneventful postoperative healing periods. Between 6 and 8 weeks after mucosal perforation and insertion of the titanium posts, however, subjective and objective symptoms of infection were registered in both patients. In addition, one of the cases exhibited dehiscence and exposure of the ceramic. The implants were removed in both individuals.

Cultivation of fibroblasts on human teeth. Ultrastructural observations of cells cultivated in multilayers

The periodontal ligament in a traumatically lost tooth is often destroyed due to drying. In attempts to restore the periodontal ligament, a technique has been worked out for using gingival biopsies as an alternative cell source. A biopsy from the attached gingiva was set up for tissue cultivation. After the establishment of a pure fibroblast culture, cells were repeatedly added to the root surfaces of 12 human teeth from which the cells and the original periodontal ligament had been removed. The teeth were examined in the transmission electron microscope. The root surface of specimens from all 12 teeth was covered with a pelliclelike material arranged in a layered pattern. The cells frequently appeared in multilayers on top of the pellicle. The cells were flattened and appeared elongated in sections. Areas of close proximity between cells and the pellicular material were seen and were interpreted as adherence junctions. The possibility that these multicellular arrangements can replace the periodontal ligament in transplantation has to be further investigated.

Supracrestal fiberotomy

Details of a surgical technique to divide the free gingival and transseptal fibers around rotated teeth that have been corrected orthodontically are outlined. The rationale of the procedure, its applications, indications, and contraindications are discussed. Supracrestal fiberotomy is not a substitute but an adjunct to normal retention procedures.

The influence of transseptal fibers on incisor position and diastema formation

Transseptal fibers are a part of the gingival group of fibers of the periodontal membrane, and they are very tough and resistant. They form a chain from tooth to tooth which, provided that it remains intact and is sufficiently strong to resist displacing muscular pressures, will preserve the contacts between the teeth throughout the arch. If the continuity of the chain is interrupted, the balance of the forces acting upon the teeth on either side of the break is upset and considerable displacements can occur. Maxillary median diastemas are classified as "simple" or "persistent" according to their etiology, and an operation to clear the upper midline suture of transeptal fibers is described as an essential part of the treatment of persistent upper median diastema.

Clinical experiences with circumferential supracrestal fiberotomy

This article has reported on a survey of 1,000 randomly selected orthodontists in the United States to ascertain the incidence of use of the circumferential supracrestal fiberotomy technique to minimize rotational relapse. It was also the purpose of the study to determine whether any problems were associated with the procedure. While the surgical technique is not widely prescribed, there are regional differences. The result of this survey tend to indicate that the technique is reasonably problem-free and that its use probably will be increasing in the future. It should be emphasized that quantitative long-term studies of the effectiveness of the procedure and of possible periodontal sequelae have to date not been reported in the literature.

The influence of primary periosteoplasty on maxillary growth and deciduous occlusion in cases of complete unilateral cleft lip and palate. A longitudinal study from infancy to the age of 5

The influence of infant periosteoplasty upon the growth of the maxilla, its form and size, and the prevalence of malocclusion in the deciduous dentition was investigated. The material consisted of 66 patients with total unilateral clefts of the primary and secondary palate. Thirty-six had periosteoplasty performed in conjunction with cleft-lip and/or palate repair. Thirty patients were operated upon without periosteoplasty and served as controls. Repair of the lip had a notable effect upon the width of the alveolar cleft and palatal cleft, both in the periosteoplasty cases and in the controls, with no certain difference between the groups. Following lip repair, the anterior width of the alveolar arch was slightly reduced. After palatal repair a further reduction was noted in the deciduous dentition, both in the cases treated with periosteoplasty and in the controls, while the posterior width of the palate across the tuberosities increased during growth. In the deciduous dentition, no differences were found in intercanine and intermolar dimensions between the periosteoplasty cases and the controls. Thus, the new bone formed in the cleft area after periosteoplasty does not seem to withstand the contracting forces introduced by palate surgery. An increased length of the buccal alveolar arch on the cleft side, compared with that on the non-cleft side, was found at both the lip repair and the palate repair in the periosteoplasty cases, as well as in the controls. In the deciduous dentition, this difference was negligible. In the deciduous dentition an anterior position of the lateral maxillary segment proved more common in the periosteoplasty cases than in the controls. On the non-cleft side, there was an increased frequency of mesial occlusion and a corresponding decrease of neutral and distal occlusion in the periosteoplasty cases. No increased frequency of anterior crossbite was found even after repeated periosteoplasty, nor was the maxillary dental-arch length unfavourably influenced. Descriptive analysis of occlusion revealed an increase of buccal crossbite in the periosteoplasty cases of a select group of the widest clefts, treated by repeated periosteoplasty. These cases also had the highest total occlusal score according to the numerical classification, while the total occlusal score after one periosteoplasty in patients with less wider clefts was smaller than in the controls. In all patients who had undergone periosteoplasty new bone formed within the alveolar cleft. A good amount of new bone developed in about half the number of cases.(ABSTRACT TRUNCATED AT 400 WORDS)

Oral surgery in general dental practice. The removal of roots

The removal of fractured teeth and retained tooth roots is described in a systematic fashion, with emphasis being placed on such procedures being carried out in general practice. The discussion is aimed at producing sound treatment planning and sequential action in order to achieve best results for patient and surgeon.