Pain after mandibular ramus block harvesting and lateral ridge augmentation with and without involvement of platelet-rich fibrin: a randomized controlled trial.

The purpose of this study was to evaluate pain after mandibular ramus block harvesting and lateral ridge augmentation. Autogenous bone block grafts were covered with platelet-rich fibrin (PRF) membranes (test group) or deproteinized bovine bone and a resorbable collagen membrane (control group). This study included 27 partially edentulous patients (test = 14, control = 13) with an indication for bone block augmentation before staged implant placement. Postoperative methylprednisolone (32 mg, day 1) and analgesics comprising ibuprofen (400 mg, four times daily) and paracetamol (1 g, four times daily) were prescribed for 1 week. Pain was recorded by the patient on a 100-mm visual analogue scale (VAS), hourly on the day of surgery and daily for the following 7 days. The average (mean ± standard deviation) maximum pain score over the whole observation period was similar in the test (13.6 ± 13.5) and control (21.0 ± 19.9) groups (P = 0.17). In conclusion, harvesting of a mandibular ramus block and lateral ridge augmentation, in conjunction with the pharmacological protocol described, is characterized by low postoperative pain. Adding PRF membranes to the surgical site generally resulted in slightly lower pain perception, although a statistically significant difference between the test and control groups was only identified on day 1 postoperative.

Short implants (≤8mm) compared to standard length implants (>8mm) in conjunction with maxillary sinus floor augmentation: a systematic review and meta-analysis.

The objective was to test the hypothesis of no difference in the treatment outcome after the installation of short implants (≤8mm) in the posterior part of the maxilla compared to standard length implants (>8mm) in conjunction with maxillary sinus floor augmentation (MSFA) using the lateral window technique, after an observation period of ≥3years. A search of the MEDLINE, Embase, and Cochrane Library databases, in combination with a hand-search of relevant journals, was conducted. The search yielded 1102 titles. Finally, three studies that fulfilled the inclusion criteria were included. All were considered to have a low risk of bias. Meta-analyses revealed no significant differences in implant survival or peri-implant marginal bone loss between the two treatment modalities. However, the use of standard length implants in conjunction with MSFA was characterized by a tendency towards more peri-implant marginal bone loss. There was no statistically significant difference between the two treatment modalities with regard to overall patient satisfaction. Short implants seem to be a suitable alternative to standard length implants in conjunction with MSFA. However, further randomized controlled trials with larger patient samples and an observation period of more than 3years are needed before one treatment modality might be considered superior to the other.

Coronectomy of mandibular third molars: a clinical and radiological study of 231 cases with a mean follow-up period of 5.7years.

Coronectomy is a widely accepted treatment for mandibular third molars that are in close relationship to the mandibular canal. However, long-term studies on morbidity following this procedure have not been presented. The aim of this study was to examine the long-term morbidity after coronectomy, with sensory disturbances of the inferior alveolar nerve (IAN) and root migration as the primary outcome variables. A total of 231 mandibular third molar coronectomies were performed in 191 patients with a mean follow-up period of 5.7years (range 1-12years). The prevalence of IAN injury was 1.3%, and 3.5% of the retained roots were removed. None of the reoperations to remove the retained roots caused IAN impairment. Infections occurred in 11.7% of the cases and all were treated with antibiotics. Overall, 97% of the retained roots showed signs of migration and 65% showed signs of rotation. Therefore, coronectomy of the mandibular third molars with an intimate relationship to the mandibular canal seems to be a safe treatment modality with a good long-term prognosis.

Ligature-associated bacterial profiles are linked to type 2 diabetes mellitus in a rat model and influenced by antibody treatment against TNF-α or RAGE.

There is a bidirectional relationship between periodontal disease (PD) and type 2 diabetes mellitus (T2D). T2D may lead to ecological perturbations in the oral environment, which may facilitate an altered microbiota. However, previous studies have been inconclusive in determining the effect of T2D on oral bacterial profiles. Therefore, we aimed to evaluate the influence of T2D on the ligature-associated bacterial profile in a diabetic rat model with PD and investigated the impact of blocking inflammatory pathways with antibodies targeting either Tumor Necrosis Factor α (TNF-α) or the receptor of advanced glycation end-products (RAGE). A total of 62 Zucker obese rats (45 T2D) and 17 lean (non-T2D) were divided into 4 treatment groups; lean with PD, obese with PD, obese with PD and anti-TNF-α treatment, and obese with PD with anti-RAGE treatment. Periodontal disease was ligature induced. Ligature-associated bacterial profiles were analyzed using Human Oral Microbe Identification Microarray (HOMIM). Ligature-associated bacterial profiles differed between lean and obese rats. Furthermore, treatment with antibodies against TNF-α or RAGE had an impact on subgingival bacterial profiles. T2D phenotypes are associated with different ligature-associated bacterial profiles and influenced by treatment with antibodies against TNF-α or RAGE.

Blockade of RAGE in Zucker obese rats with experimental periodontitis.

BACKGROUND AND OBJECTIVE: Periodontitis and type 2 diabetes mellitus (T2D) are two interrelated chronic diseases. Periodontitis is more prevalent in patients with T2D than in healthy subjects, and studies indicate that periodontitis impacts the metabolic control of patients with T2D. Hyperglycemia in T2D leads to the formation of advanced glycation end-products (AGEs). Binding of AGEs to the receptor of AGE (RAGE) elicits an increased inflammatory response that may be a key modulator linking the two diseases. The present study aimed to elucidate the effect of blocking the RAGE on the interrelationship between periodontitis and T2D in a rat model of both diseases. MATERIAL AND METHODS: Zucker obese rats (HsdHlr:ZUCKER-Lepr fa/fa ) and their lean littermates were divided into five treatment groups, with and without periodontitis. Monoclonal anti-RAGE IgG3 were injected into the rats three times a week. The diabetic state was evaluated by oral glucose tolerance tests (OGTTs), the homeostasis model assessment (HOMA), concentration of free fatty acids and repeated measurements of blood glucose. Markers of systemic inflammation, including interleukin (IL)-1ß, IL-6 and tumor necrosis factor α, were evaluated in plasma. Kidney complications were evaluated by quantitative real-time PCR, the creatinine clearance rate, the albumin excretion rate and kidney hypertrophy. Periodontitis was evaluated by morphometric registration of alveolar bone loss and radiographic recording of bone support. RESULTS: The diabetic state was improved by antibody treatment for 4 wk, resulting in a lower area under the glucose concentration curve during OGTTs, lower insulin levels and a lower HOMA. Furthermore, the antibody treatment resulted in milder kidney complications, as evaluated by measuring the albumin excretion rate and the kidney weight. There was no impact of periodontal inflammation on the level of complications. Periodontal bone support was influenced by diabetes, but the altered diabetic status as a result of treatment with anti-RAGE Ig had no effect on periodontitis. CONCLUSION: In this study, treatment with anti-RAGE IgG3 resulted in improved glucose tolerance and attenuated renal complications. However, no effect was observed on the diabetes-associated periodontitis in Zucker obese rats. Furthermore, periodontitis had no effect on diabetic markers or renal complications. Therefore, activation of RAGE is important in the development of T2D.

Effect of unilateral mandibular distraction osteogenesis on mandibular morphology in rabbits with antigen-induced temporomandibular joint arthritis.

Aim was to evaluate effect of unilateral distraction osteogenesis (DO) on mandibular morphology in rabbits with antigen-induced arthritis in the temporomandibular joint (TMJ). Forty 8-week-old rabbits were divided into four groups. In groups A,C, arthritis was induced in the right TMJ. Groups A,B underwent DO. Group D served as control group. Cephalometric analysis of mandibular angle, mandibular ramus height, mandibular collum height, and total posterior mandibular height was done on CT-scans preoperatively (T0), after distraction (T1), and at euthanasia (T2). Two-factor ANOVA evaluated the effect of DO and antigen-induced arthritis. No effect of DO or arthritis was observed on mandibular angle or mandibular collum height. For T0-T1, DO increased mandibular ramus height 12.3% (95% CI 5.2-19.4%) in group B (P=0.001) and total posterior mandibular height 6.2% (95% CI 0.3-12.1%) in group A (P=0.04) and 10.0% (95% CI 4.3-15.7%) in group B (P=0.001). For T1-T2, no significant changes occurred in arthritic rabbits (group A). In conclusion, DO increased total posterior mandibular height in rabbits with arthritis. Postoperatively, no significant effect of DO was observed in rabbits with arthritis. Mandibular DO could be a viable treatment modality in patients with TMJ-arthritis.

Audit of a 5-year radiographic protocol for assessment of mandibular third molars before surgical intervention.

OBJECTIVES: To perform an audit of a three-step protocol for radiographic examination of mandibular third molars before surgery. METHODS: 1769 teeth underwent surgery. A standardized three-step radiographic protocol was followed: (1) panoramic imaging (PAN), (2) stereoscanography (SCAN) and (3) CBCT. If there was overprojection between the tooth and the canal in PAN, SCAN was performed. If the tooth was determined to be in close contact with the canal in SCAN, CBCT was performed. Close contact between the tooth and the canal was assessed in all images, and patient-reported sensory disturbances from the alveolar inferior nerve were recorded after surgery. The relation between the final radiographic examination and sensory disturbances was determined. Logistic regression analysis tested whether signs for a close contact in PAN/SCAN could predict no bony separation between the tooth and canal in CBCT. RESULTS: 46% of teeth underwent PAN, 31% underwent SCAN and 23% underwent CBCT as the final examination. 21% underwent all three radiographic examinations. 53/76% of teeth with close relation to the canal in PAN/SCAN showed no bony separation in CBCT; if there was close relation in PAN/SCAN, there was 1.6/4.3 times higher probability that no bony separation existed in CBCT. 16 cases of sensory disturbances were recorded: 4 operations were based on PAN, 8 on SCAN and 4 on CBCT. CONCLUSIONS: The radiographic protocol was in general followed. SCAN was superior to PAN in predicting no bony separation between the tooth and the canal in CBCT, and there was no relation between sensory disturbances and radiographic method.

Influence of cone beam CT on treatment plan before surgical intervention of mandibular third molars and impact of radiographic factors on deciding on coronectomy vs surgical removal.

OBJECTIVES: To assess the influence of cone beam CT (CBCT) on treatment plan before surgical intervention of mandibular third molars and to identify radiographic factors with an impact on deciding on coronectomy. METHODS: 186 mandibular third molars with an indication for surgical intervention underwent a radiographic examination with two methods: (1) panoramic imaging in combination with stereo-scanography and (2) CBCT. After the radiographic examination a treatment plan (TP) was established: either surgical removal (Sr) or coronectomy (Co). The first TP was based on the panoramic image and stereo-scanogram, while the second TP was established after CBCT was available. Logistic regression analyses were used to identify factors predisposing for Co after CBCT. RESULTS: Treatment was performed according to the second TP. Agreement between the first and second TP was seen in 164 cases (88%), while the TP changed for 22 teeth (12%) after CBCT. Direct contact between the third molar and the mandibular canal had the highest impact on deciding on Co [odds ratio (OR) = 101.8, p < 0.001]. Direct contact was not a sufficient factor, however; thus, lumen narrowing of the canal (OR = 38.9-147.2, p < 0.001) and canal positioned in a bending or a groove in the root complex (OR = 32.8, p = 0.016) were additional canal-related factors for deciding on Co. CONCLUSION: CBCT influenced the treatment plan for 12%. Direct contact in combination with narrowing of the canal lumen and canal positioned in a bending or a groove in the root complex observed in CBCT images were significant factors for deciding on coronectomy.

Thermography as a quantitative imaging method for assessing postoperative inflammation.

OBJECTIVE: To assess differences in skin temperature between the operated and control side of the face after mandibular third molar surgery using thermography. METHODS: 127 patients had 1 mandibular third molar removed. Before the surgery, standardized thermograms were taken of both sides of the patient's face using a Flir ThermaCam™ E320 (Precisions Teknik AB, Halmstad, Sweden). The imaging procedure was repeated 2 days and 7 days after surgery. A region of interest including the third molar region was marked on each image. The mean temperature within each region of interest was calculated. The difference between sides and over time were assessed using paired t-tests. RESULTS: No significant difference was found between the operated side and the control side either before or 7 days after surgery (p > 0.3). The temperature of the operated side (mean: 32.39 °C, range: 28.9-35.3 °C) was higher than that of the control side (mean: 32.06 °C, range: 28.5-35.0 °C) 2 days after surgery [0.33 °C, 95% confidence interval (CI): 0.22-0.44 °C, p < 0.001]. No significant difference was found between the pre-operative and the 7-day post-operative temperature (p > 0.1). After 2 days, the operated side was not significantly different from the temperature pre-operatively (p = 0.12), whereas the control side had a lower temperature (0.57 °C, 95% CI: 0.29-0.86 °C, p < 0.001). CONCLUSIONS: Thermography seems useful for quantitative assessment of inflammation between the intervention side and the control side after surgical removal of mandibular third molars. However, thermography cannot be used to assess absolute temperature changes due to normal variations in skin temperature over time.

Immediately restored one-piece single-tooth implants with reduced diameter: one-year results of a multi-center study.

OBJECTIVES: The aim of the present multi-center study was to evaluate the treatment outcome of immediately restored one-piece single-tooth implants with a diameter of 3 mm after 1 year. MATERIAL AND METHODS: A total of 57 one-piece implants (NobelDirect 3.0) were inserted in 47 patients (26 females, 21 males) with a mean age of 31 years (range: 17-76 years) at five different centers. The implants replaced maxillary lateral incisors and mandibular incisors. The implants were placed either in conjunction with tooth extraction or in healed sites, and all implants were immediately restored with a provisional resin crown. If needed, the abutment part of the implant was prepared before crown cementation. The permanent crown was placed after 1.9-14.5 months. Radiographs were taken at implant insertion as well as after 6 and 12 months to evaluate the peri-implant marginal bone level and bone loss. Moreover, plaque, bleeding on probing and complications were assessed. RESULTS: A total of 44 patients (23 females, 21 males) with 54 implants were available for the 1-year follow-up. One implant was lost, thus the 1-year implant survival was 98%. A statistically significant mean marginal bone loss was observed between baseline and 6 months (1.1 mm, range: -0.7 to 4.4 mm; n=49) and between baseline and 12 months (1.6 mm, range: -0.8 to 4.6 mm; n=50). A total of 18% of the implants were characterized by a bone loss of more than 3 mm. No bleeding on probing was observed around 83% of the implants. Plaque was registered at 15% of the implants. The most common complications were related to the provisional crown, i.e. fracture (n=3) and loss of retention (n=3). CONCLUSIONS: A high 1-year implant survival was observed in the present study. However, the excessive peri-implant marginal bone loss around several implants indicates that this implant should be used with caution until further studies have been conducted.

Maxillary sinus floor augmentation with Bio-Oss or Bio-Oss mixed with autogenous bone as graft in animals: a systematic review.

The objective of the present systematic review was to test the hypothesis of no differences between the use of Bio-Oss or Bio-Oss mixed with autogenous bone as graft for maxillary sinus floor augmentation (MSFA) applying the lateral window technique, as evaluated in animals. A MEDLINE (PubMed), Embase, and Cochrane Library search in combination with a hand-search of relevant journals was conducted by including animal studies published in English from 1 January 1990 to 1 June 2010. The search provided 879 titles and 14 studies fulfilled the inclusion criteria. The volumetric stability of the graft improved significantly with increased proportion of Bio-Oss. Bone regeneration, bone-to-implant contact (BIC), biomechanical implant test values, and biodegradation of Bio-Oss after MSFA with Bio-Oss or Bio-Oss mixed with autogenous bone have never been compared within the same study in animals. Thus, the hypothesis of no differences between the use of Bio-Oss and Bio-Oss mixed with autogenous bone as graft for MSFA could neither be confirmed nor rejected based on existing animal studies.

Implant treatment in periodontitis-susceptible patients: a systematic review.

Implant treatment in individuals with periodontitis-associated tooth loss is frequently debated. The objective of the present systematic review was to assess the principles and outcome of implant treatment in periodontitis-susceptible patients. Studies considered for inclusion were searched in MEDLINE (PubMed) and relevant journals were hand-searched. The search was restricted to studies published in English from 1980 to 2006. Prospective and retrospective cohort studies assessing implant treatment in partially and totally edentulous individuals with a history of periodontitis-associated tooth loss were included when the follow-up period was >1 year, when more than five patients were included in the study, and when the treatment involved titanium implants. The outcome measures were loss of suprastructures, loss of implants, loss of teeth, health status of peri-implant tissues and health status of periodontal tissues. Screening of eligible studies and data extraction were conducted by the reviewer. A total of 23 studies were identified. The survival rates of suprastructures and implants were high in individuals with a history of periodontitis-associated tooth loss. Therefore, implant treatment in periodontitis-susceptible patients is not contraindicated provided adequate infection control and an individualized maintenance programme. However, the higher incidence of peri-implantitis may jeopardize the longevity of the implant treatment. Consequently, further long-term prospective studies of sufficient numbers of well-characterized patients are needed before definitive conclusions can be drawn about the long-term outcome of implant treatment in periodontitis-susceptible patients.

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.

Dentine-bonded resin composite (Retroplast) for root-end filling: a prospective clinical and radiographic study with a mean follow-up period of 8 years.

AIM: To evaluate treatment outcome after using a resin composite (Retroplast, RP) in combination with a dentine-bonding agent (GLUMA) as root-end filling material after 1 year as well as after more than 5 years (final examination). Also, the influence of various pre-, intra- and postoperative factors on the treatment outcome was studied. METHODOLOGY: All patients (87) undergoing root-end resection consecutively treated by root-end filling with RP on an incisor, canine, pre-molar, or first molar (87 teeth, 118 roots) were initially enrolled in the study. RP was applied on the entire resected surface that was prepared to a slightly concave shape and after conditioning with EDTA and GLUMA. The treatment outcome involving subjective, clinical and radiographic parameters was evaluated after 1 year and at the final examination. A total of 27 patients (36 roots) were excluded from the study because of unavailability of follow-up (19) and extraction of the operated tooth for reasons other than failed surgery (8). Consequently, 60 patients (82 roots) were included in the final material. The mean follow-up period at the final examination was 8 years (range: 6.5-9 years). RESULTS: The radiographic evaluation at the final examination revealed that 77%, 5%, 7% and 11% of the treated roots were characterized by complete, incomplete, uncertain and unsatisfactory healing, respectively. A total of 95% of the roots classified as completely healed at the 1-year control were also completely healed at the final examination. Two roots (5%) showing complete healing at the 1-year control revealed unsatisfactory healing at the final examination because of displaced or lost RP-filling. Moreover, 60% of the roots with uncertain healing at the 1-year control demonstrated complete or incomplete healing at the final examination. The classification according to subjective, clinical and radiographic parameters revealed that 78% of the teeth were characterized by a successful treatment outcome at the final examination. Evaluation of the influence of various pre-, intra- and postoperative factors on the treatment outcome revealed that the radiographic classification at the final examination was exclusively influenced by the radiographic classification at the 1-year control (P < 0.001). CONCLUSIONS: The present long-term study indicates that RP can be used for root-end filling with a successful treatment outcome.

A prospective, randomized, comparative clinical study of resin composite and glass ionomer cement for retrograde root filling.

OBJECTIVE: To compare the clinical and radiographic treatment outcome of retrograde root filling with either dentin-bonded resin composite (Retroplast, RP) or glass ionomer cement (Chelon-Silver, CS). STUDY DESIGN: A prospective, randomized clinical study of 134 consecutive patients with indication of retrograde root filling of an incisor, canine, premolar, or first molar. Either RP or CS was chosen at random as retrograde filling material. Either material was applied onto the entire resection surface after prepared slightly concave. This preparation technique makes a sealing of the entire resection surface possible and prevents marginal contraction gaps during polymerization. A total of 122 patients were available for 1-year follow-up. RESULTS: After 1 year the proportion of successful cases was significantly higher in the RP group (73%) than in the CS group (31%) (p<0.001). Doubtful healing with a need for a longer observation period was seen in 17% of the RP cases and 19% of the CS cases. The proportion of failures in the RP group (10%) was significantly lower than that in the CS group (50%) (p<0.001). Most of the unsuccessful CS cases failed due to loosening of the retrograde filling. CONCLUSIONS: Dentin-bonded RP applied onto the entire, slightly concave resection surface is a predictable apical sealant characterized by a high success rate. In contrast, retrograde root filling with CS results in an unacceptably high failure rate due to insufficient bonding strength to the concave resection surface.

Application of the Third Molar Eruption Predictor to periapical radiographs.

The aim of this study was to test whether the Third Molar Eruption Predictor, developed for panoramic radiographs, can also be applied to periapical radiographs. The Third Molar Eruption Predictor is a transparent device (US patent 5,816,814), not commercially available, and developed for prediction of future eruption or impaction of third molars. The material consisted of periapical radiographs of mandibular third molars taken from the lateral projection without angulation of the central beam. The radiographs taken at the mean age of 20.6 years (SD +/- 1.4 years) were retrospectively available from a four-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. Initially unerupted or partially erupted third molars (n=43) in 28 dental students were analyzed. Clinical statuses of the third molars were available at baseline and four years later. The device was calibrated using the method of simple proportions and Bayes' Decision Theory. The predictions made with the calibrated device were in conformity with the final clinical outcome in 84% of the cases. It was concluded that the Third Molar Eruption Predictor may also be used on periapical radiographs after calibration of the device.

Accuracy of the Third Molar Eruption Predictor in predicting eruption.

OBJECTIVE: To evaluate the possibility of applying the Third Molar Eruption Predictor to all panoramic radiographs. STUDY DESIGN: Panoramic radiographs were retrospectively analyzed from a 4-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. The radiographs, taken at a mean age of 20.6 years, included 45 unerupted or partially erupted mandibular third molars in 28 subjects. Because the device was calibrated both with simple proportions and by use of the methods of Bayes' Decision Theory, the separation point of the device was therefore adjusted at 12 mm from the distal surface of the second molar. RESULTS: The predictions of future eruption or impaction made with the calibrated device and the actual clinical outcome 4 years later were in conformity for 80% of the mandibular third molars. CONCLUSION: The Third Molar Eruption Predictor may be applied to all panoramic radiographs, but it seems to require calibration before use.

Marburg and Ebola virus infections in laboratory non-human primates: a literature review.

BACKGROUND AND PURPOSE: Several non-human primate species are used as laboratory animals for various types of studies. Although importation of monkeys may introduce different diseases, special attention has recently been drawn to Marburg and Ebola viruses. This review presented here discusses the potential risk of these viruses for persons working with non-human primates as laboratory animals by focusing on epidemiology, virology, symptoms, pathogenesis, natural reservoir, transmission, quarantine of non-human primates, therapy, and prevention. CONCLUSION: A total of 23 Marburg and Ebola virus outbreaks causing viral hemorrhagic fever has been reported among humans and monkeys since the first outbreak in Marburg, Germany in 1967. Most of the 1,100 human cases, with nearly 800 deaths, developed in Africa due mainly to direct and intimate contact with infected patients. Few human cases have developed after contact with non-human primates used for various scientific purposes. However, adequate quarantine should be applied to prevent human infections not only due to Marburg and Ebola viruses, but also to other infective agents. By following proper guidelines, the filovirus infection risk for people working with non-human primates during quarantine exists, but is minimal. There seems to be little risk for filovirus infections after an adequate quarantine period. Therefore, non-human primates can be used as laboratory animals, with little risk of filovirus infections, provided adequate precautions are taken.

Osseointegration of subperiosteal implants using bovine bone substitute and various membranes.

An earlier study revealed incomplete osseointegration of individually made titanium subperiosteal implants covered by ePTFE membranes and fixated to the rabbit tibial bone surface. In addition, the newly-formed bone was dominated by large marrow spaces. In this subsequent study, subperiosteal implants were also fixated on the bone surface of both tibia of 9 Copenhagen White rabbits. Bio-Oss particles were packed densely covering the entire implant surface. One of 3 different membranes covered the implant and the particles. The membranes used were the degradable Polyglactin 910 mesh, a degradable bilayer collagen membrane and the non-degradable ePTFE membrane. Undecalcified sections were prepared for histologic evaluation after a 12 weeks' observation period. All 18 subperiosteal implants were completely osseointegrated. In addition, the marrow spaces were reduced compared to our previous study. The Bio-Oss particles proved to be biocompatible and osteoconductive. The ePTFE membranes revealed neither signs of collapse nor adjacent infiltration of inflammatory cells. The Polyglactin 910 mesh and the bilayer collagen membranes collapsed slightly. There were signs of resorption of the surface of the newly-formed bone under the degradable membranes. The cause of resorption can not be documented.

A 41-year history of a mandibular subperiosteal implant.

The subperiosteal implant was originally described in the 1940s. The inadequate long-term results of subperiosteal implants are in contrast to the excellent results documented for endosseous osseointegrated oral implants. Consequently, subperiosteal implants and other soft-tissue-anchored implants should not be used presently. Furthermore, these implants are seldom seen today, because they generally were removed rather shortly after placement. The present report documents a full 41-year history of a mandibular subperiosteal implant inserted in 1957 by focusing upon the consequences of not removing an implant in spite of continuous periods of complications during 4 decades. Implant exposure, inflammation, infection, and fistula formation occurred persistently. Total implant removal was refused by the patient in 1973. After 25 years without control, tremendous resorption of the mandible was observed in 1998. Consequently, the entire implant was then removed. Placement of osseointegrated oral implants was impossible without extensive autogenous bone grafting. The present report has demonstrated that regular control of patients with subperiosteal implants is mandatory. Furthermore, subperiosteal implants should definitely be removed, if continuous periods of complications occur.