Biomedical subjects

Gerry M Raghoebar

Publications and source records attributed to Gerry M Raghoebar.

35 records · Page 2Linked to original sources

PubMed2003

Effects of maxillary sinus floor elevation surgery on maxillary sinus physiology.

In a prospective study, the effects of elevation surgery of the maxillary sinus floor on maxillary sinus physiology were assessed. Seventeen consecutive patients without preoperative anamnestic, clinical and radiological signs of maxillary sinusitis underwent sinus floor elevation surgery with iliac crest bone grafts. All patients were subjected to unilateral endoscopic examination of the maxillary sinus, taking of a biopsy specimen from the sinus floor mucosa, and collection of a sinus lavage-fluid aspirate. This triad of evaluations was performed immediately preceding the elevation procedure, and 3 months (at implant insertion) and 9 months (at uncovering of implants) postoperatively. All procedures were performed under general anesthesia. Preoperatively, three out of 17 patients showed pre-existing mucosal pathology endoscopically, while the 3- and 9-month results revealed the presence of mucosal pathology in four and two patients, respectively. The 3-month microbiological evaluation showed a significant increase in cultures with bacterial growth, while the 9-month culture results were comparable to the preoperative status of the maxillary sinus. Morphologically, neither fibrosis nor an altered inflammatory response or thickening of the epithelium and lamina propria was observed postoperatively. The number of goblet cells in the epithelial layer was increased. From this study it is concluded that the effect of maxillary sinus floor elevation surgery with autogenous bone grafts does not appear to have clinical consequences in patients without signs of pre-existing maxillary sinusitis.

Adult↗

PubMed2003

Early loading of endosseous implants in the augmented maxilla: a 1-year prospective study.

In 10 patients, 68 endosseous implants were inserted in the augmented edentulous maxilla using a one-stage implant placement technique. Three months before implant insertion, the width and height of the alveolar crest were augmented with autologous bone grafts from the iliac crest. In all cases, the resulting bone volume was sufficient for implant insertion. According to an early loading protocol, the implant-supported overdenture was fabricated 2 months after insertion of the implants. Evaluation was performed according to a standardised protocol immediately and 1 year after fabrication of the prosthetic construction. The protocol included assessment of both clinical (bleeding score, pocket depth, implant mobility) and radiographic (marginal bone level on standardised radiographs) parameters. Three implants in two patients in the upper jaw were lost (survival rate: 95.6%). The peri-implant tissues had a healthy appearance and bone loss was minimal. Overall, the patients were very satisfied with the prosthetic construction. From this preliminary study, it is concluded that in selected cases, early loading of implants may develop into a predictable treatment modality after augmentation of the maxilla.

Adult↗

PubMed2003

3-year prospective multicenter study on one-stage implant surgery and early loading in the edentulous mandible.

BACKGROUND: The long-term success rates achieved in dental implantology suggest that flexibility might well exist within the various implant systems to a degree that an altered protocol (ie, one-stage surgery and immediate or early loading) can be performed under controlled conditions. However, before variations of the protocol can be considered for general use, they must be subjected to critical analysis, particularly with respect to the predictability of osseointegration, alteration of soft tissue barrier, and relative change in bone height around the implants. PURPOSE: The aim of this prospective multicenter study was to evaluate implant survival and periimplant conditions around endosseous implants placed in a one-stage surgical procedure and early loading. MATERIALS AND METHODS: A total of 170 implants were placed in 40 patients with mandibular edentulism and were functionally loaded within 6 weeks with overdentures (n = 30) or fixed prostheses (n = 10). All patients and prosthetic constructions were evaluated according to a standardized protocol during 3 years of follow-up. Cumulative implant survival rates were calculated, and implant loss in relation to implant size and bone quality and quantity were evaluated. Furthermore, the protocol included assessment of clinical (plaque and bleeding scores, prosthesis stability) and radiographic parameters. RESULTS: Over a period of 3 years, the implant survival rate was 93% for both implants and prostheses (fixed or removable). No implants were lost after the first year of loading. The periimplant tissues were in a healthy condition. Mean marginal bone resorption from the time of loading to the 3-year follow-up was 0.41 mm (SD 0.52). CONCLUSIONS: From this study it may be concluded that early loading results in good implant survival and proper periimplant health in edentulous mandibles.

Adult↗

PubMed2003

Mandibular fracture caused by peri-implant bone loss: report of a case.

BACKGROUND: A major complication related to excessive bone loss around implants is fracture of the mandible. This complication is most likely to occur in a very atrophic mandible. A 57-year-old woman presented with progressive pain and swelling that had been present for 5 days in the right frontal region of the mandible. An intraoral radiograph revealed a radiolucency around one of the implants in the interforaminal region. METHODS: Ten years earlier, 4 hollow-screw implants of 10 mm length had been inserted in the interforaminal region of the edentulous mandible. Throughout the 10-year postoperative period, no adverse clinical events were seen; however, during the last 7 years, no radiographic follow-up was performed. Mobility was tested after removal of the bar, on which one of the implants appeared to be mobile. The mobile implant was removed together with the fibrous tissue. RESULTS: At a recall visit 2 weeks later, a radiograph revealed a fracture of the mandible at the explantation site. Characteristic features of the hollow-screw implant are the hollow body and the transverse openings in the side walls of the implant. It has been reported that these characteristic features can enhance infection and rapid bone loss, but a case of mandibular fracture has never been described. CONCLUSION: Radiographs should be taken on a regular and perhaps more frequent basis to diagnose excessive bone loss, so that measures can be taken to prevent the risk of mandibular fracture.

Alveolar Bone Loss↗

PubMed2002

Two-stage IMZ implants and ITI implants inserted in a single-stage procedure. A prospective comparative study.

The aim of this study was to evaluate the feasibility of using a two-stage implant system in a single-stage procedure and to study the impact of the microgap at crestal level and to monitor the microflora in the peri-implant area. Forty edentulous patients (Cawood & Howell class V-VI) participated in this study. After randomisation, 20 patients received two IMZ implants inserted in a single-stage procedure and 20 patients received two ITI implants. After 3 months, overdentures were fabricated, supported by a bar and clip attachment. A standardised clinical and radiographic evaluation was performed immediately after denture insertion and 6 and 12 months later. Twelve months after loading, peri-implant samples were collected with sterile paper points and analysed for the presence of putative periodontal pathogens using culture techniques. One IMZ implant was lost due to insufficient osseointegration. With regard to the clinical parameters at the 12 months evaluation, significant differences for plaque score and probing pocket depth (IMZ: mean 3.3 mm, ITI: mean 2.9 mm) were found between the two groups. The mean bone loss in the first year of functioning was 0.6 mm for both groups. Prevotella intermedia was detected more often in the ITI group (12 implants) than in the IMZ group (three implants). Porphyromonas gingivalis was found in three patients. In one of these patients an implant showed bone loss of 1.6 mm between T0 and T12. Some associations were found between clinical parameters and the target microorganisms in the ITI group. These associations were not present in the IMZ group. The short-term results indicate that two-stage implants inserted in a single-stage procedure may be as predictable as one-stage implants. The microgap at crestal level in nonsubmerged IMZ implants seems to have no adverse influence on the peri-implant microbiological colonisation and of crestal bone loss in the first year of functioning. The peri-implant sulcus can and does harbour potential periodontal pathogens without signs of peri-implantitis during the evaluation period of 1 year.

Alveolar Bone Loss↗

PubMed2002

Vertical distraction of the severely resorbed edentulous mandible: a clinical, histological and electron microscopic study of 10 treated cases.

The aim of this study was to evaluate the clinical and histomorphological results of distraction of the severely resorbed edentulous mandible. In a group of 10 edentulous patients suffering from insufficient retention of their mandibular denture related to a severely resorbed mandible, the anterior segment was augmented as a preimplant surgical procedure using the nonvoluminous Groningen Distraction Device (GDD). Two months after the last day of distraction, a bone biopsy was taken with a trephine, both distraction screws were replaced by endosseous implants and the guide screw was removed. The biopsies were examined by means of light microscopy (LM) and transmission electron microscopy (TEM). Radiographical and histomorphological examination of the biopsies revealed the presence of two cortical zones, one at each end of the biopsies, a poorly mineralized, fibrous interzone in the middle of the distraction gap, and two zones of mineralization between the central fibrous and the peripheral cortical zones. Formation of lamellar bone parallel to the distraction vector was clearly visible in the mineralization zone as well as signs of remodelling at the borderline between the native cortical bone and the generate. Clinical examination showed in all patients that the anterior segment distracted from the mandible body was sufficiently enlarged to enable insertion of endosseous implants with a length of at least 12 mm. One implant was lost during the healing phase, but was successfully replaced thereafter. Implant retained overdentures were fabricated 3 months after implantation. All patients have good function 11.2 +/- 4.3 months after the end of treatment. From this study it is concluded that the GDD has proven to be a reliable tool for augmentation of the anterior segment of a severely resorbed edentulous mandible enabling osseointegration of endosseous load-bearing implants.

Aged↗

PubMed2002

Two-part implants inserted in a one-stage or a two-stage procedure. A prospective comparative study.

OBJECTIVE: The aim of this study was to evaluate the feasibility of using a two-part implant system in a one-stage procedure and to monitor the microflora in the peri-implant area in relation to clinical and radiographic outcome. MATERIAL AND METHODS: After randomisation, 40 edentulous patients (Cawood & Howell class V-VI) received two IMZ implants in the anterior mandible inserted by either a one-stage (n = 20) or a two-stage (n = 20) surgical procedure for overdenture treatment. A standardised clinical and radiographic evaluation was performed after denture insertion as well as 6 and 12 months thereafter. Twelve months after loading, peri-implant samples were collected and analysed for the presence of putative periodontal pathogens using culture technique. RESULTS: No striking differences were found between the two groups with regard to the clinical parameters during the evaluation period. The mean bone loss in the first year of functioning was 0.6 mm in both groups. With regard to the gingiva score, plaque score, bleeding score or bone loss between T0 and T12, no associations were found with the presence of the cultured microorganisms. An association was present between pockets >or= 4 mm and the presence of Peptostreptococcus micros in the two-stage group. CONCLUSIONS: The short-term results indicate that two-part implants inserted in a one-stage procedure may be as predictable as inserted in the common two-stage procedure. The peri-implant sulcus can and does harbour potential periodontal pathogens without significant signs of tissue breakdown.

Colony Count, Microbial↗

PubMedDate not supplied

Microbiota around root-form endosseous implants: a review of the literature.

Although high success rates for root-form endosseous implants have been reported, failures occasionally occur, and these implants must be removed. At least 10% of the failures have been suggested to be the result of peri-implantitis. There is some evidence that periodontal pathogens, mainly those belonging to the group of gram-negative anaerobic rods, play a role in the etiology of peri-implantitis. This article provides an overview of the literature associated with common peri-implant microbiology and an assessment as to whether bacteria associated with periodontitis exert a possible risk for peri-implant tissue breakdown. The peri-implant area is colonized by a large variety of oral microbial complexes. The microflora of the oral cavity prior to implant placement determines the composition of the microflora in the peri-implant area. Implants involved in peri-implantitis are colonized with large amounts of gram-negative anaerobic bacteria, including Fusobacteria, spirochetes, Bacteroides forsythus, and "black-pigmented bacteria" such as Prevotella intermedia, Prevotella nigrescens, and Porphyromonas gingivalis. Also, Actinobacillus actinomycetemcomitans can be isolated from these lesions. Thus, the microflora of peri-implantitis lesions resembles that of adult or refractory periodontitis. However, the presence of periodontal pathogens does not always lead to a destructive process. Therefore, the etiologic role of specific microorganisms in implant failure related to infection is still not resolved. Controversy remains as to whether organisms recovered from the original microflora cause the failure (and if so to what extent) or merely result from the infection. Nevertheless, there is accumulating evidence that bacteria cause the disease, while the individual's genetic makeup and environmental influences determine the severity of the disease.

Dental Implantation, Endosseous↗

PubMedDate not supplied

Clinical and radiologic evaluation of 2-stage IMZ implants placed in a single-stage procedure: 2-year results of a prospective comparative study.

PURPOSE: The aim of this study was to evaluate the feasibility of using a 2-stage implant system in a single-stage procedure and to study the impact of the microgap between the implant and the abutment. MATERIALS AND METHODS: Sixty edentulous patients (Cawood class V or VI) participated in this study. After randomization, 20 patients received 2 IMZ implants placed in a single-stage procedure, 20 patients received 2 IMZ implants placed in the traditional 2-stage procedure, and 20 patients were treated with 2 ITI implants (single-stage procedure). The implants were placed in the canine area of the mandible. After 3 months, mandibular overdentures were fabricated, supported by a bar-and-clip attachment. A standardized clinical and radiographic evaluation was performed immediately after prosthesis placement and after 12 and 24 months. RESULTS: One IMZ implant of the 1-stage group and 1 IMZ implant of the 2-stage group were lost after 6 and 12 months, respectively. Apart from several significant but clinically irrelevant differences, the 3 groups did not appear to differ markedly with regard to clinical parameters during the evaluation period. The mean bone loss within the first 2 years of functioning (1.1 mm IMZ 1-stage, 0.8 mm IMZ 2-stage, 1.2 mm ITI) was comparable for the 3 groups. DISCUSSION AND CONCLUSIONS: The results of this study suggest that dental implants designed for a submerged implantation procedure can also be used in a single-stage procedure and may be as predictable as when the same implants used in a 2-stage procedure or as 1-stage implants. Placement of the microgap at the crestal level in 2-stage implants did not appear to have an adverse effect on the amount of peri-implant bone loss at 2 years in this study population.

Alveolar Bone Loss↗

PubMedDate not supplied

Mucosal and radiographic aspects during the healing period of implants placed in a one-stage procedure.

PURPOSE: The aim of this prospective clinical trial was to compare peri-implant clinical and radiographic parameters following the placement of nonsubmerged two- and one-stage implants. MATERIALS AND METHODS: Patients were randomly assigned to the IMZ group (20 patients receiving two IMZ two-stage implants in a one-stage procedure) or ITI group (20 patients receiving two ITI implants in the conventional one-stage procedure). The healing period was defined as an 18-week unloaded osseointegration period and a 1-year functional period during which maturation of bone took place. Twelve weeks after implant placement, fabrication of an overdenture with a bar-clip attachment system was started; it was placed at 18 weeks. RESULTS: None of the implants were lost during the osseointegration period; one IMZ implant was removed during the functional period because of mobility. There was no significant difference in Gingival Index between the two groups at all evaluation periods. The mean bone loss during the functional period was 0.6 mm in both groups. A high number of healing abutments loosened in the IMZ group. CONCLUSION: Clinical and radiographic parameters of two-stage implants placed in a one-stage procedure and one-stage implants are comparable during the healing period. Healing abutments of the IMZ implant system loosen easily.

Alveolar Bone Loss↗

PubMedDate not supplied

Treatment for an endosseous implant migrated into the maxillary sinus not causing maxillary sinusitis: case report.

Placement of endosseous implants in the maxilla has been proven to be a reliable treatment modality. If there is lack of supporting bone, the placed implant may not have enough primary stability and may migrate into the maxillary sinus. Displaced implants must be removed. If there are no signs of maxillary sinusitis, augmentation of the resulting alveolar defect can be performed during the same procedure.

Alveolar Ridge Augmentation↗

PubMedDate not supplied

Comparison of implant-retained mandibular overdentures and conventional complete dentures: a 10-year prospective study of clinical aspects and patient satisfaction.

PURPOSE: The aim of this prospective randomized clinical trial was to evaluate 10 years of treatment of patients receiving a mandibular implant-retained overdenture (IRO) or a conventional complete denture (CD). MATERIALS AND METHODS: One hundred twenty-one edentulous patients were treated with an IRO (2 endosseous implants, n = 61) or a conventional CD (n = 60). Clinical aspects and patient satisfaction were evaluated. One year after placement of the denture, unsatisfied patients of the CD group were given the opportunity to receive implants. RESULTS: In the IRO group, 4 implants were lost during the first year and 4 implants were lost during the next 4 years. Between 5 and 10 years, no implants were lost (survival rate: 93%). In the CD group, 24 patients (40%) chose an IRO between 1 and 10 years. DISCUSSION: Patients in the IRO group were significantly more satisfied than patients in the CD group after 1 year (satisfaction score 8.3 versus 6.6 on a scale of 1 to 10), after 5 years (7.4 versus 6.4), and after 10 years (7.7 versus 6.8). CONCLUSION: The mean satisfaction score of the CD group (including patients who later received implants) was still lower than that of the IRO group, in spite of the opportunity for retreatment with IROs. Endosseous implants had a high survival rate after 10 years of follow-up.

Dental Implants↗

PubMedDate not supplied

The extremely resorbed mandible: a comparative prospective study of 2-year results with 3 treatment strategies.

PURPOSE: The aim of this prospective clinical study was to compare the clinical and radiographic results of 3 modes of implant treatment in combination with an overdenture in patients with extremely resorbed mandibles. The 3 treatment strategies used were a transmandibular implant, augmentation of the mandible with an autologous bone graft followed by placement of 4 endosseous implants, and the placement of 4 endosseous implants only. MATERIALS AND METHODS: Sixty edentulous patients met the inclusion criteria and were assigned according to a balanced allocation method to 1 of the 3 groups. Postoperative complications, implant survival, periodontal indices, change in mandibular bone height, and prosthetic complications were assessed during a 2-year evaluation period. RESULTS: During the evaluation period significantly more implants were lost in the transmandibular implant and the augmentation groups compared to the group with endosseous implants only. Except for the Bleeding Index and the Periotest values, the periodontal parameters did not differ significantly among the groups. In all 3 groups, there was no significant bone loss at most locations. Minimal prosthetic retreatment was necessary. DISCUSSION: Although implant loss is a frequently used outcome measure for success, the necessity of retreatment seems to be of more relevance for both the patient and the clinician. CONCLUSIONS: The results of this study suggested that patients with extremely resorbed mandibles can be treated with implants alone in this patient population.

Alveolar Bone Loss↗

PubMedDate not supplied

Does ultrasound stimulate osteoconduction? A placebo-controlled single-blind study using collagen membranes in the rat mandible.

PURPOSE: To investigate whether ultrasound can stimulate osteoconduction in the mandible, an attempt was made to stimulate the osteoconductive process with low-intensity pulsed ultrasound in rats. MATERIALS AND METHODS: In 64 rats, a 5.0-mm diameter circular mandibular defect was made in the ramus and, subsequently, covered on both sides with collagen membranes. Two groups were studied, an ultrasound treatment group and a placebo treatment group. At 2 and 4 weeks, the remaining defect area was measured using microradiographs, and the amount of osteoconduction was expressed as the percentage of defect closure. RESULTS: At 2 and 4 weeks, there was no significant difference in the percentage of defect closure between the groups. DISCUSSION: An explanation may be that ultrasound does not exert an effect in an area where wound healing is already expected to be at an optimal level. CONCLUSION: There was no evidence that low-intensity pulsed ultrasound stimulates osteoconduction in a bone defect in the rat mandible that is covered by a collagen membrane.

Absorbable Implants↗

PubMedDate not supplied

Oral rehabilitation with dental implants in oligodontia patients.

PURPOSE: The aim of this retrospective report was to evaluate the treatment outcome of oral rehabilitation with dental implants in oligodontia patients. MATERIALS AND METHODS: Thirteen oligodontia patients treated with dental implants were examined clinically and radiographically (follow-up 3 +/- 2 years, range 1 to 8 years). In addition, patient-mediated concerns of satisfaction, treatment experience, and level of impairment of oral functions were assessed with questionnaires. RESULTS: In general, all patients were satisfied with the implant treatment and experienced the treatment as nonaggravating. There was significant functional improvement, with an implant survival rate of 86% and 96% for the maxilla and mandible, respectively. CONCLUSION: Dental implants can play an important role in the oral rehabilitation of patients with oligodontia. Patients were generally satisfied with the overall treatment experience and reported significant functional improvement. Implant survival rate was comparable with previous reports.

Adolescent↗

PubMedDate not supplied

Correction of a malpositioned endosseous implant by a segmental osteotomy: a case report.

A mandibular overdenture supported by 2 or 4 endosseous implants has been proven to be a reliable treatment modality for patients suffering from conventional denture problems. However, fabrication of an implant-retained mesostructure to support an overdenture is not possible in all cases. Malpositioning of implants is a common cause of failure in such cases. A case is presented in which a ball attachment caused pain and severe swelling of the floor of the mouth because of the lingual inclination of an endosseous implant. The lingual inclination of the implant was corrected by a segmental osteotomy. Six weeks later, prosthodontic treatment began, and the resultant overdenture supported by a Dolder bar was quite acceptable for the patient.

Bone Plates↗

PubMedDate not supplied

Implant-retained mandibular overdentures versus conventional dentures: 10 years of care and aftercare.

PURPOSE: This 10-year prospective, randomized, clinical trial investigated the treatment outcome of edentulous patients treated with mandibular overdentures retained by 2 endosseous implants compared with conventional dentures in patients with or without vestibuloplasty. MATERIALS AND METHODS: One hundred fifty-one edentulous patients (5 groups) with a symphyseal mandibular bone height between 8 and 25 mm participated. Sixty-two patients were treated with an overdenture retained by 2 implants (groups 1 and 3), 59 patients were treated with a conventional denture (groups 2 and 5), and 30 patients were treated with a conventional denture after preprosthetic vestibuloplasty (group 4). Patients who received conventional dentures but preferred implants later on could undergo implant surgery after 1 year of their initial treatment, but were analyzed in their original group. The prosthetic and surgical care and aftercare were scored during a 10-year evaluation period. RESULTS: One hundred thirty-three patients completed the 10-year follow-up evaluations. Forty-four percent of patients treated with conventional dentures switched within 10 years to implant-retained overdentures, versus 16% of the patients who were treated with conventional dentures after vestibuloplasty. On average, a greater time investment and more treatment sessions were needed in patients treated with implant-retained overdentures compared to patients treated with conventional dentures. CONCLUSION: Patients treated with an implant-retained overdenture need more treatment interventions and treatment time than patients treated with conventional dentures.

Adult↗