AbstractAim: The aim of the present study was to evaluate early (1–2 weeks) loading of Astra Tech implants in the anterior part of the mandible, between the mental foramina, in a 3‐year clinical and radiological study.Material and methods: Early loading of Astra Tech Tioblast implants was performed in the lower jaw in 20 patients. Prosthetic loading of the implants was done between 1 and 2 weeks following surgery. The patients were divided in two groups with 10 patients in each group. One group had conventional implant surgery in edentolous mandibles, while in the second group extraction of remaining teeth and immediate placement of implants and early loading was carried out.Results: Clinical success rate was very high in all cases. However radiological examination showed a slightly inferior outcome after immediate placement in fresh extraction sockets and early loading of the implants with regard to the marginal bone level. There was however no significant difference between the groups.

A prospective clinical and radiographic study has been carried out in 49 patients with a total of 252 implants. In a mixture of 17 edentulous mandibles, 20 edentulous maxillas, nine partial edentulous cases, and three single-tooth cases, prosthetic treatments were aimed at getting as close an adaptation as possible between gingival tissues and superstructure. The shortest possible abutments were used, and the implants were surgically positioned subcrestally. The results during a 5-year follow-up showed a success rate of 98.9% for fixtures in the lower jaw and 96.3% for the upper jaw with a total success rate of 97.3%. The marginal bone reduction during five years with closely adapted superstructures was 0.11 mm in the mandible and 1.1 mm in the maxilla. Our results support the use of close gingivally adapted superstructures, although oral hygiene controls and instructions are regularly advisable.

BACKGROUND:Previous experimental studies have shown a higher degree of bone-implant contact for surface-enlarged implants compared with machined implants. Yet, there is insufficient evidence that such implants show higher stability and an increased survival rate.PURPOSE:The purpose of this investigation was to study the integration and stability of grit-blasted implants with retention elements on the implant neck, with and without marginal bone defects, compared with machined implants without retention elements.MATERIALS AND METHODS:After tooth extraction of the mandibular premolars in six dogs, two grit-blasted, partly microthreaded Astra Tech implants and one standard Brånemark implant were bilaterally placed in each dog. On one side, 3 x 3 mm large buccal defects were created, to expose three to four implant threads. The contralateral side served as control, and no defects were made. The animals were sacrificed after 4 months of healing. Implant stability was measured using resonance frequency analysis at implant installation and after 4 months of healing. Histologic and histomorphometric evaluation was made after 4 months of healing.RESULTS:Resonance frequency analysis indicated that all implants in the test and control groups were osseointegrated after 4 months, with a tendency toward higher implant stability for the Astra Tech implants. There was a statistically significant higher increase in resonance frequency for the Astra test implants compared with their corresponding controls. Histology and histomorphometry showed well-integrated implants with varying degrees of bone repair at the defect sites. The greater bone-implant contact for the Astra implants was statistically significant. No significant difference between the implants in amount of bone filling the threads was recorded.CONCLUSIONS:The Astra Tech implants tested showed a higher degree of bone-implant contact and higher level of bone regenerated at defect sites compared with the Brånemark implants. Resonance frequency analysis demonstrated a significantly higher increase in the Astra test implants compared with their control groups than did the Brånemark test implants versus their controls.

An experimental rabbit bone graft model for the study of bone formation and remodeling around titanium implants is described. A 2.5-cm long radius bone segment served as an onlay graft. Two commercially pure (c.p.) titanium implants were inserted into the bone graft prior to fixation to the inferior border of the mandibular base with osteosynthesis titanium screws. Each animal was operated twice, allowing follow-up periods of 6 weeks on one side and 6 months on the contralateral side. In order to study bone remodeling by means of fluoroscopy the animals received single injections of tetracyclin and alizarine complexone 2 weeks and 1 week, respectively, prior to sacrifice by perfusion fixation with glutaraldehyde. The bone and implants were excized en bloc, postfixed and embedded in plastic resin. Stained and unstained thin ground sections as well as microradiographed thick sections were produced for light microscopic morphometry and fluoroscopy. After 6 weeks, osteoclastic/osteoblastic activity was primarily observed in the graft-recipient contact area and in the intracortical compartment of the graft bone. New bone formation observed on the implant surface originated from the recipient site. The bone formation was evident also in the implant-graft interface. At 6 weeks the average bone fill of the implant threads was 28.4% which increased to 36.4% after 6 months as measured by morphometry. An average of 17.6% bony contact was measured after 6 weeks which increased to 29.7% 6 months after surgery. The graft bone had reduced in size from an average of 39.5% after 6 weeks down to 24.8% after 6 months (P < 0.05). It is concluded that the described experimental model can serve as a useful method for the study of implant healing in onlay grafts.

BACKGROUND High failure rates have been presented for implants placed in grafted bone. The bone graft-implant interface constitutes a most complex healing situation, where the time scale for osseointegration and development of implant stability currently is not known. PURPOSE The aim of the study was to measure the stability of implants placed in grafted bone after various follow-up periods. METHODS Implant stability measurements by means of resonance frequency analysis were performed in 10 patients previously treated with a Le Fort I osteotomy and interpositional bone grafts. The implants were placed 3 to 4 months after the grafting procedure. Sixty-seven Brånemark implants were subjected to resonance frequency analysis measurements at fixture placement and up to 5.5 years after implant surgery. Periapical radiographs were used for assessment of marginal bone levels. RESULTS The radiographic examinations showed marginal bone loss with time during the 5.5-year follow-up. The resonance frequencies varied from 5860 to 8440 Hz. When accounting for abutment length and marginal bone level, there was a tendency of increasing resonance frequency with time. Two implants with low resonance frequencies failed during the prosthetic phase. CONCLUSION The results indicate an increased implant stability with time, which may reflect bone formation, remodeling, and maturation at the implant interface.

A group of 19 patients where traumatic root fractures were treated with surgical extrusion procedure has been clinically and radiographically followed up for 10 years. Except for one out of 21 intraalveolar transplanted roots all functioned with different kinds of crown restorations and without pathological complications. The surgical extrusion method should thus be a useful tool in the treatment of teeth with cervical root-fractures and also teeth with deep cervical root caries which are difficult to treat conservatively.

Thirty patients with severely resorbed maxillae were treated in a one-stage procedure using bone graft and implant placement. A horseshoe-shaped bone graft was taken from the iliac wing and fixed to the residual maxillary ridge using titanium implants, which supported the prostheses placed after a 6-month healing period. The material constituted two groups: a development group, the first 10 patients; and a routine group, the following 20 patients. At the 3-year follow-up, the implant survival was 87.5% and the prosthesis stability was 100% in the routine group. The probing depth did not change during the follow-up period, while the grafted region decreased in volume during the first postoperative year. The patients reported improved chewing ability and improved life quality. Very few technical and prosthodontic complications occurred.

A combination of horseshoe-shaped iliac bone grafts and Brånemark implants was used in 30 patients with severely resorbed maxillary alveolar ridges. All patients were followed clinically for 2 years and evaluated with regard to prosthesis stability, fixture survival, wound healing complications, and soft tissue conditions. Surgery was performed by the same oral surgeons using identical procedures, and the prosthetic treatment was performed by the same prosthodontist. The development group included the first 10 patients and the routine group included the following 20. Fixture survival in the development group was 54.4%, whereas 88.3% of the fixtures in the routine group have survived after 2 years. The average fixture survival in the study was 77.4%. Three patients in the development group lost all fixtures, primarily the result of trauma to the grafted region. With respect to the difficult situation many of these patients experienced, the survival rate should be considered most acceptable.

An experimental study in the rabbit has been undertaken to evaluate differences in bone regeneration in and around solid (Alveograf) and porous (Interpore 200) hydroxyapatite granulae. Material was placed into experimentally made bone defects and in half of the defects HA was also mixed with fibrin sealant (Tisseel). Material alone or mixed with Tisseel was also placed subperiosteally adjacent to the mandibular bone. The observation time was six months. The study showed, however, no difference in bone regeneration around solid or porous hydroxyapatite granula nor could we see differences when mixed with Tisseel or not. Implant material placed subperiosteally did not induce bone formation nor did it provoke bone resorption. The use of fibrin sealant (Tisseel) made the hydroxyapatite material much more easy to handle and to retain in the tissue.

One of a series of patients with extremely resorbed maxillae treated with bone grafts from the hip in combination with Brånemark self-tapping fixtures died in a car accident 4 months after implant surgery. Autopsy specimens from this patient were analyzed to evaluate the amount and extent of "osseointegration" after 4 months of healing. Histologic examination revealed that minimal bone was in direct contact with the titanium and the general pattern was that of soft tissue screw anchorage. There were no signs of sequestering of the transplanted bone. The connection between the nasal cavity and the sinus mucosa with respect to the transplants seemed to be without adverse reactions. The superior part of the transplant did show signs of newly formed bone. The grafted specimens showed indications of delayed bone response compared to the nongrafted situation. All implants were clinically stable as studied postmortem.

Dr. Elisabeth Nystrom, Department of Oral and Maxillofacial Surgery, University of Umea, S-901 87 Umea, Sweden.

27 patients subjected to various orthognathic surgery procedures were studied preoperatively and during a period of 18 months postoperatively by a team of psychologists to evaluate the patients' own opinions concerning the indication for surgery, information about the surgical procedure, the postoperative period and the long-term aesthetic and functional results. The patients were interviewed 5 times: 2 days before surgery, 2 days after surgery and 2, 6 and 18 months after surgery. The decision to undergo surgery was taken after a long period of time, 4 years on average, and half of the patients were influenced by their family or dentist before they made their decision. 60% gave three or more reasons for surgery, 85% mentioned functional problems, 74% facial appearance and 59% craniomandibular symptoms. 63% indicated that the facial appearance problems had negatively influenced their personal life and 44% their social life. Women experienced this problem more often than men. The results showed that the overall majority of patients were relieved of their presurgical problems. The aesthetic improvement was better than expected. It was found that improvements in facial features had a beneficial influence on the patients as individuals and also on their social life situation.

The soft tissue response to genioplasty procedures was studied in 65 patients. The patients were divided into four groups depending on the direction of the genioplasty. In 17 patients straight anterior repositioning was made (group I), in 12 patients posterior repositioning of the chin (group II), in 19 patients vertical reduction of the chin (group III) and in group IV superior-anterior repositioning of the chin. The predictability of the procedures varied. The soft tissue response was equal to the bone movement in the anterior repositioning but less predictable in the posterior direction or when combined with vertical reduction.

Horse-shoe shaped bone grafts from the hip together with biotes self-tapping fixtures were used to rehabilitate patients with extremely resorbed upper jaws. Our experience and results from the 10 first consecutive case have been analyzed to form the base for further use of the method. We have lost eight fixtures out of 57 so far. Surgical complications with exposure of the bone transplant have occurred in three patients. A surprisingly good recovery from the hip has been seen in all of the patients. Certain technical precautions such as construction of a splint in the dentulous or partially dentulous jaw to prevent occlusal trauma towards the transplant have been made to avoid complications such as rupture of the mucosal flap. The method should be used with great care and the case meticulously chosen to avoid individuals who do not have the right motivation for the long-lasting and demanding surgical and prosthetic procedures. The combined use of implants and transplants should not be used routinely until a long-term evaluation of the method has been made to minimize potential drawbacks.

A case of an unusual site of salivary gland tissue is presented. The lesion appeared as a radiolucency between the apices of the lateral incisor and canine in a 57-year-old male patient and simulated a periapical lesion. The canine was found vital.

Light and electron microscopy were used to analyze nine therapy-resistant and asymptomatic human periapical lesions, which were removed as block biopsies during surgical treatment of the affected teeth. The cases that required surgery represented about 10% of all of the cases which received endodontic treatment and root fillings during the period 1977 to 1984. These cases revealed periapical lesions when they were examined 4 to 10 yr after treatment. The biopsies were processed for correlated light and electron microscopy. Six of the nine biopsies revealed the presence of microorganisms in the apical root canal. Four contained one or more species of bacteria and two revealed yeasts. Of the four cases in which bacteria were found, only in one biopsy could they be found by light microscope. In the other three specimens, the bacterial presence could be confirmed only after repeated electron microscopic examination of the apical root canal by serial step-cutting technique. Among the three cases in which no microorganisms could be encountered, one showed histopathological features of a foreign body giant cell granuloma. These findings suggest that in the majority of root-filled human teeth with therapy-resistant periapical lesions, microorganisms may persist and may play a significant role in endodontic treatment failures. In certain instances such lesions may also be sustained by foreign body giant cell type of tissue responses at the periapex of root-filled teeth.

Bone grafts from the hip in combination with Brånemark self-tapping fixtures have been used to rehabilitate patients with extremely resorbed maxillae. Experiences and results from the first ten consecutive cases have been analyzed to form the basis for further use of the method. Eight of 57 fixtures placed have been lost to date. Surgical complications, including exposure of the bone transplant, have occurred in three patients. The method should be used with caution, and cases should be meticulously chosen to exclude those who do not have proper motivation to endure the long-lasting and demanding surgical and prosthetic procedures required. The combined use of implants and transplants should not be used routinely until a long-term evaluation of the method and results has been made.

International Endodontic JournalVolume 21, Issue 4 p. 277-282 Survival of Arachnia propionica in periapical tissue U. SJÖGREN, Corresponding Author U. SJÖGREN Department of Endodontics, University ofUmeå, Umeå, SwedenDr U. Sjögren, Department of Endodontics, Faculty of Odontology, University of Umeå, S-901 87 Umeå, Sweden.Search for more papers by this authorR. P. HAPPONEN, R. P. HAPPONEN Institute of Dentistry, University of Turku, Turku, FinlandSearch for more papers by this authorK. E. KAHNBERG, K. E. KAHNBERG Department of Oral Surgery, University ofUmeå, Umeå, SwedenSearch for more papers by this authorG. SUNDQVIST, G. SUNDQVIST Department of Endodontics, University ofUmeå, Umeå, SwedenSearch for more papers by this author U. SJÖGREN, Corresponding Author U. SJÖGREN Department of Endodontics, University ofUmeå, Umeå, SwedenDr U. Sjögren, Department of Endodontics, Faculty of Odontology, University of Umeå, S-901 87 Umeå, Sweden.Search for more papers by this authorR. P. HAPPONEN, R. P. HAPPONEN Institute of Dentistry, University of Turku, Turku, FinlandSearch for more papers by this authorK. E. KAHNBERG, K. E. KAHNBERG Department of Oral Surgery, University ofUmeå, Umeå, SwedenSearch for more papers by this authorG. SUNDQVIST, G. SUNDQVIST Department of Endodontics, University ofUmeå, Umeå, SwedenSearch for more papers by this author First published: July 1988 https://doi.org/10.1111/j.1365-2591.1988.tb01012.xCitations: 94AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume21, Issue4July 1988Pages 277-282 RelatedInformation

An experimental study in the white rat (Sprague-Dawley) was undertaken to evaluate the frequency of fisula formation after palatal midline osteotomies as used in surgical-orthodontic "rapid-expansion" procedures. The mucosal incision was made in the palatal midline above the osteotomy region. The healing process was followed during three and six weeks in two groups of animals. In one of the groups the width of the osteotomy was one millimeter and in the other two millimeters. The frequency of fistula formation was in the larger osteotomy group higher and reached 85% after six weeks healing. The frequency of fistula formation was never less than 33%. Osteoid formation in the osteotomy region was almost nill in all cases.