Biomedical subjects

Gerry M Raghoebar

Publications and source records attributed to Gerry M Raghoebar.

At least 19 recordsLinked to original sources

PubMed2006

Rehabilitation of oral function in head and neck cancer patients after radiotherapy with implant-retained dentures: effects of hyperbaric oxygen therapy.

Surgical treatment of malignancies in the oral cavity and subsequent radiotherapy often result in an anatomic and physiological oral condition unfavorable for prosthodontic rehabilitation. The objective of this prospective study was to assess the effect of hyperbaric oxygen therapy on treatment outcome (condition of peri-implant tissues, implant survival, oral functioning and quality of life) of prosthodontic rehabilitation with implant-retained lower dentures in radiated head and neck cancer patients 6 weeks and 1 year after placing the new dentures. The treatment outcome was assessed in a group of 26 head neck cancer patients who were subjected to radiotherapy after tumour surgery. Standardized questionnaires were completed and clinical and radiographic assessments were performed. After randomization, endosseous Brånemark implants were placed in the anterior part of the mandible either under antibiotic prophylaxis (13 patients) or under antibiotic prophylaxis combined with pre and postsurgery hyperbaric oxygen (HBO) treatment (13 patients). In the HBO and non-HBO group eight implants (implant survival 85.2%) and three implants (implant survival 93.9%) were lost, respectively. Peri-implant tissues had a healthy appearance in both groups. Osteoradionecrosis developed in one patient in the HBO group. All patients functioned well with their implant-retained lower denture. The quality of life related to oral functioning and denture satisfaction were improved to a comparable extent in the HBO and non-HBO group. Implant-retained lower dentures can improve the quality of life related to oral functioning and denture satisfaction in head and neck cancer patients. Adjuvant hyperbaric oxygen therapy could not be shown to enhance implant survival in radiated mandibular jaw bone.

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PubMed2006

Resorbable screws for fixation of autologous bone grafts.

The aim of this study was to evaluate the suitability of resorbable screws made of poly (D.L-lactide) acid (PDLLA) for fixation of autologous bone grafts related to graft regeneration and osseointegration of dental implants. In eight edentulous patients suffering from insufficient retention of their upper denture related to a severely resorbed maxilla, the floor of both maxillary sinus and width of the alveolar crest were augmented with an autologous bone graft from the iliac crest. Randomly, the bone graft used to augment the alveolar crest was fixed with two titanium screws on one side and two resorbable screws on the other side (split-mouth design). Three months after the reconstruction, a bone biopsy was taken with a trephine including one resorbable screw (N = 8). Subsequently, six implants were placed in the left and right posterior maxilla. Six months later, at the abutment connection, a bone biopsy was taken including the other resorbable screw (N = 8). The biopsies were processed for light microscopic examination. In addition, clinical parameters were scored. Wound healing was uneventful. Clinically no difference in wound healing was observed between sides treated with either a resorbable or titanium screw. No implants were lost. Six months after implantation, implant retained overdentures could be fabricated in all patients. All patients functioned well with their overdentures (follow-up 22.2 +/- 4.3 months). Three as well as 9 months after insertion (remnants of), the resorbable screws were still visible after reflecting the mucoperiosteum. Histological examination confirmed that a considerable quantity of remnants of the resorbable screws was still present, although areas with some fragmentation of the PDLLA were also observed. The screws were separated by a fibrous tissue layer containing many giant cells from the bone. Particles of PDLLA were observed within these giant cells. This study revealed that resorbable screws made of PDLLA can be used for fixation of bone grafts. The bulk of the PDLLA material is still present after 9 months.

Absorbable Implants↗

PubMed2006

Long-term evaluation of hollow screw and hollow cylinder dental implants: clinical and radiographic results after 10 years.

BACKGROUND: In 1988, an implant manufacturer offered a new dental implant system, with a wide choice of hollow cylinder (HC) and hollow screw (HS) implants. The purpose of this retrospective study of HS and HC implants was to evaluate clinical and radiographic parameters of peri-implant tissue and to analyze surgical and prosthetic aftercare. METHODS: A total of 89 HS and 26 HC implants in 38 edentulous patients were available for complete evaluation. The patients were treated with overdentures stabilized by two or four implants. The follow-up period was 10 years. RESULTS: The results of the clinical evaluation showed a mean sulcus probing depth of 3.3+/-1.3 mm (range=2 to 10 mm). The mean radiographic bone loss was 2.2+/-2.1 mm (range=0.1 to 12.2 mm). One implant (HS) was removed during the osseointegration period. Three other implants (two HS and one HC) in three patients had to be removed after 10 years. The survival rate of the HS implant (96.6%) was comparable to the HC implant (96.1%). The success rate of the HS implant (93.3%) was slightly more favorable compared to the HC implant (88.5%). The HS and HC implants met the Albrektsson criteria of success. CONCLUSIONS: HS and HC implants provide a stable base for long-term support of a mandibular overdenture. Furthermore, it is important to monitor peri-implant bone level by taking annual radiographs and measuring probing depth, especially after prolonged service.

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PubMed2006

Feasibility and influence of the microgap of two implants placed in a non-submerged procedure: a five-year follow-up clinical trial.

BACKGROUND: The aim of this study was to evaluate the feasibility of using a two-piece implant system in a non-submerged procedure and to study the impact of the microgap between the implant and abutment. METHODS: Sixty edentulous patients (Cawood Class V-VI) participated in this study. After randomization, 20 patients received two two-piece implants placed in a non-submerged procedure, 20 patients received two two-piece implants placed in the traditional submerged procedure, and 20 patients were treated with two one-piece dental implants placed in the traditional non-submerged procedure. The implants were placed in the mandible for overdenture treatment. A standardized clinical evaluation was performed and radiographs were taken immediately after denture insertion and yearly up to 5 years. Peri-implant samples were collected 12, 36, and 60 months after loading with sterile paper points and analyzed for the presence of putative periodontal pathogens using culture techniques. RESULTS: One two-piece implant of the non-submerged group and one two-piece implant of the submerged group were lost after 6 and 12 months, respectively. After 5 years of functioning, no significant clinical, radiological, or microbiological differences were found between the three groups. No association was found between the level of the microgap and the amount of bone loss. CONCLUSIONS: The results of this study indicate that dental implants designed for a submerged implantation procedure can also be used in a non-submerged procedure and may be as predictable as when used in a submerged procedure or as one-piece implants. The microgap at the crestal level in two-piece implants does not appear to have an adverse effect on the amount of peri-implant bone loss.

Alveolar Bone Loss↗

PubMed2005

Ultrasound to stimulate early bone formation in a distraction gap: a double blind randomised clinical pilot trial in the edentulous mandible.

OBJECTIVE: In a double blind randomised clinical pilot trial, it was investigated whether low intensity pulsed ultrasound therapy stimulates early bone formation in a distraction gap created in a severely resorbed mandible. DESIGN: Eight patients underwent a mandibular vertical distraction over an average distance of 6.6+/-1.1mm. Ultrasound self-therapy or placebo therapy was started on the first day of distraction and continued daily until the implants were inserted. After 31+/-3.8 days of consolidation, the distraction device was removed, a transmandibular biopsy was taken, and two endosseous implants were inserted. RESULTS: All patients complied well with ultrasound therapy. During an average of 30.1+/-4.1 months follow-up, no complications did occur. Microradiographic examination of the biopsies revealed a comparable mean area of mineralised tissue in the distraction gap of 1.9+/-1.7mm(2) in the ultrasound treatment group and 1.9+/-1.3mm(2) in the placebo treatment group. Histological examination indicated that active woven bone was present within the distraction gap just adjacent to the osteotomy plane, with no apparent differences between the treatment groups. The lamellar bone formation outside the distraction gap appeared to have started as well. CONCLUSION: During a 31-day consolidation period, ultrasound treatment does not appear to stimulate bone formation in the severely resorbed vertical distracted mandible and it seems that this period is too short to evaluate properly if there is an effect. Therefore, a longer consolidation period has to be studied.

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PubMed2005

Distraction osteogenesis in the irradiated mandible. A case report.

BACKGROUND: Distraction osteogenesis has been suggested as a relatively simple method of mandibular reconstruction following ablative head and neck surgery. Some authors report good results in irradiated patients while other authors report limitations with this group of patients. PATIENT: In a 72-year-old male an attempt was made to reconstruct the irradiated mandible using distraction osteogenesis. RESULTS: Distraction osteogenesis only resulted in an enlarged soft tissue envelope, while there was no evidence of bone formation in the distraction gap. CONCLUSION: Based on this experience and a search of the literature, it is hypothesized that distraction osteogenesis is only a reliable reconstructive method in irradiated patients if the cumulative dose to the mandibular bone at the distraction site does not exceed a certain maximum still to be defined.

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PubMed2005

Mandibular overdentures supported by two or four endosseous implants. A 5-year prospective study.

OBJECTIVE: The aim of this 5-year prospective comparative study was to evaluate treatment outcome (survival rate, condition of hard and soft peri-implant tissues, patient satisfaction, prosthetic and surgical aftercare) of mandibular overdentures supported by two or four implants. MATERIAL AND METHODS: Sixty edentulous patients with a mandibular height between 12 and 18 mm participated. Thirty patients were treated with an overdenture supported by two IMZ implants (group A) and 30 patients were treated with an overdenture supported by four IMZ implants (group B). Standardised clinical and radiographic parameters were evaluated 6 weeks after completion of the prosthetic treatment and after 1, 2, 3, 4 and 5 years of functional loading. Prosthetic and surgical aftercare was scored during the evaluation period. RESULTS: One implant was lost (group A) during the healing period. There were no significant differences with regard to any of the studied clinical or radiographic parameters of the peri-implant tissues between the groups. None of the patients reported sensory disturbances in the lip or chin region. No differences in satisfaction were observed between the groups. With regard to aftercare, there was a tendency of a greater need of prosthetic interventions in group A, while correction of soft-tissue problems was restricted to patients of group B. CONCLUSION: There is no difference in clinical and radiographical state of patients treated with an overdenture on two or four implants during a 5-year evaluation period. Patients of both groups were as satisfied with their overdentures.

Adult↗

PubMed2005

Does platelet-rich plasma promote remodeling of autologous bone grafts used for augmentation of the maxillary sinus floor?

The aim of this study was to evaluate the effect of platelet-rich plasma (PRP) on remodeling of autologous bone grafts used for augmentation of the floor of the maxillary sinus. In five edentulous patients suffering from insufficient retention of their upper denture related to a severely resorbed maxilla, the floor of both maxillary sinus was augmented with an autologous bone graft from the iliac crest. Randomly, PRP was added to the bone graft used to augment the floor of the left or right sinus (split-mouth design). Three months after the reconstruction, bone biopsies were taken with a trephine from the planned implant sites (N=30). Subsequently, three implants were placed in the left and right posterior maxilla. Microradiograms were made of all biopsies (N=30), whereafter the biopsies were processed for light microscopic examination. In addition, clinical parameters were scored. Wound healing was uneventful, clinically no difference was observed between the side treated with PRP or not. Also microradiographical and histomorphological examination of the biopsies revealed no statistical difference between the PRP- and non-PRP side. One implant placed in the PRP side of the graft was lost during the healing phase. Implant-retained overdentures were fabricated 6 months after implantation. All patients functioned well (follow-up 20.2+/-4.3 months). In this study, no beneficial effect of PRP on wound healing and bone remodeling was observed. It is posed that PRP has no additional value in promoting healing of grafted non-critical size defects.

Blood Platelets↗

PubMed2005

A new index for rating aesthetics of implant-supported single crowns and adjacent soft tissues--the Implant Crown Aesthetic Index.

OBJECTIVES: The important item of aesthetics is rarely included in evaluation studies. The aim of this study was to develop and validate an index for rating aesthetics of implant-supported single crowns and adjacent soft tissues. MATERIAL AND METHODS: Nine items were selected, which have an influence on the aesthetic result. The items are based on the anatomic form, colour and surface characteristics of the crown and on the anatomic form, colour and surface characteristics of the peri-implant soft tissues. Two oral-maxillofacial surgeons and two prosthodontists rated 24 implant-supported single-tooth restorations and adjacent soft tissues on a form with the nine items of the rating index. The rating was carried out twice by each of the examiners. Weighted Cohen's kappa was calculated to express the intra- and interobserver agreement. RESULTS: Intraobserver results indicated that the agreement between the first and second rating of both the prosthodontists was good (both 0.7) and that the agreement of the oral-maxillofacial surgeons was moderate (0.49 and 0.56). The best interobserver agreement was found between the two prosthodontists (0.61, good agreement). CONCLUSIONS: The Implant Crown Aesthetic Index is an objective tool in rating aesthetics of implant-supported single crowns and adjacent soft tissues. The rating is best be carried out by one prosthodontist to have the highest reliability.

Crowns↗

PubMed2004

Therapeutic ultrasound to stimulate osteoconduction; A placebo controlled single blind study using e-PTFE membranes in rats.

To decrease healing time of bone defects covered with osteoconductive membranes, an attempt was made to stimulate the osteoconductive process with therapeutic ultrasound. In 72 rats, a circular mandibular defect was created and covered on both sides with an e-PTFE membrane. A control group, an ultrasound treatment group and a placebo treatment group were studied. At 2 and 4 weeks, the osteoconduction was expressed as the percentage of defect closure using digitized microradiographs. At 2 weeks, there was no significant difference in the percentage of defect closure between the groups. At 4 weeks, there was significantly more bone defect closure in the placebo group (77.9%) as compared to the control group (59.3%). Membrane ultrasound attenuation measurements indicated that the membrane blocks most of the applied ultrasound. In conclusion, low intensity pulsed ultrasound does not appear to significantly stimulate osteoconduction into a bone defect in the rat mandible that is covered by an e-PTFE membrane.

Animals↗

PubMed2004

Ultrasound to stimulate mandibular bone defect healing: a placebo-controlled single-blind study in rats.

PURPOSE: Because of the limitations of the body to heal large maxillofacial bone defects, an attempt was made to stimulate mandibular defect healing with low intensity pulsed ultrasound in rats. This ultrasound consists of a 1.5-MHz pressure wave administered in pulses of 200 microsec, with an average intensity over space and time of 30 mW. cm(-2). MATERIALS AND METHODS: In 72 rats, a 5.0-mm-diameter circular mandibular defect was created. Three groups were studied: an ultrasound treatment group, a placebo treatment group, and a control group. Ultrasound and placebo treatment involved a daily treatment for 20 minutes at the site of the defect under general anesthesia. At 2 and 4 weeks, the region of bone growth within the defect was measured using microradiographs and the amount of defect healing was expressed as the percentage of defect closure. RESULTS: At 2 and 4 weeks, there was no statistical significant difference in the percentage of defect closure between the groups. CONCLUSION: Low-intensity pulsed ultrasound does not stimulate bone defect healing in the case of a large mandibular defect in the rat.

Animals↗

PubMed2004

A controlled clinical trial of implant-retained mandibular overdentures: 10 years' results of clinical aspects and aftercare of IMZ implants and Brånemark implants.

The aim of this prospective randomized controlled clinical trial was to evaluate the clinical outcomes and prosthetic aftercare of edentulous patients with a mandibular overdenture retained by two IMZ implants or two Brånemark implants during a 10-year period. Patients were allocated to the IMZ group (n=29) or the Brånemark group (n=32) by a computerized balancing method. In the IMZ group, four implants were lost during the 10-year follow-up (survival rate: 93%). In the Brånemark group, nine implants were lost (survival rate: 86%). All patients were re-operated successfully. Multiple prosthetic revisions were necessary in both groups; especially the precision attachment system in the overdenture (23% of the total number of revisions) and the denture base and teeth (26% of the total number of revisions) were subject to frequent fracture. From this study, it can be concluded that both the IMZ implant and the Brånemark implant systems supporting an overdenture are functioning well after 10 years of follow-up. There are no indications of a worsening of clinical or radiographical state after 10 years.

Alveolar Bone Loss↗

PubMed2004

Mandibular overdentures supported by two Brånemark, IMZ or ITI implants: a 5-year prospective study.

OBJECTIVES: The aim of this prospective comparative study was to evaluate the survival rate and the condition of the peri-implant tissues of the IMZ implant system (two-stage cylindertype), the Brånemark implant system (two-stage screwtype) and the ITI implant system (one-stage screwtype) supporting a mandibular overdenture during a 5-year follow-up period. MATERIAL AND METHODS: Three groups of 30 edentulous patients were treated with two endosseous implants in the interforaminal region of the mandible. Clinical and radiographic parameters were evaluated immediately after completion of the prosthetic treatment and after 1, 2, 3, 4 and 5 years of functional loading. RESULTS: The five-year survival rate is 98.3% for the IMZ group, 98.3% for the Brå group and 100% for the ITI group. Mean scores on indices for plaque, calculus, gingiva and bleeding were very low at all evaluation periods. Mean marginal bone loss over a period of 5 years, was 1.4 mm for the IMZ group, 0.7 mm for the Brå group and 0.9 mm for the ITI group. CONCLUSION: It is concluded that two implants placed in the interforaminal region, connected with a bar, supply a proper base for the support of a mandibular overdenture in the edentulous patient. After 5 years no clinically relevant and statistically significant radiographic changes had developed between the three implant systems.

Alveolar Bone Loss↗

PubMed2004

A technique for standardized evaluation of soft and hard peri-implant tissues in partially edentulous patients.

BACKGROUND: There is a growing need to evaluate the esthetics of implant-supported crowns and bridges. An important tool for such an evaluation is standardized assessment of the soft and hard peri-implant tissue levels. METHODS: A simple acrylic device has been developed for reliable and reproducible assessment of soft and hard peri-implant tissues using standardized color slides and standardized dental x-rays. With this device, changes in both the soft and hard tissues around implant-supported crowns can be evaluated as a function of time. The reproducibility of the technique was tested on color slides as well as on dental x-rays in a series of implant-supported crowns and their neighboring teeth. RESULTS: The reproducibility of this technique was excellent. The measuring errors for repeated measurements of the soft and hard tissues were 0.14 +/- 0.02 mm and 0.13 +/- 0.01 mm, respectively. CONCLUSIONS: The device is a reliable tool to assess changes in both soft and hard tissues around crowns and implants over time. Likewise, it is suggested that this technique also can be used to objectively assess soft and hard tissue changes around natural teeth with or without prosthetic restorations.

Acrylic Resins↗

PubMed2003

Mandibulotomy and implant insertion.

BACKGROUND: A mandibulotomy can be necessary to approach a tumor in the oral cavity or oropharynx. The aim of this study was to develop and prospectively evaluate a technique enabling simultaneous performance of a mandibulotomy and insertion of endosseous implants in the same area. METHODS: In five edentulous patients such a procedure was performed. The pilot drilling of the implants was done before performing the mandibulotomy. After tumor resection, reconstruction, and restoration of the continuity of the mandible, the final drilling and insertion of the implants were completed. In total, 20 implants were inserted. All patients received radiation therapy within 6 weeks after surgery. Implant-supported overdentures were fabricated 6 months after irradiation. At regular time intervals, a standardized clinical and radiographic evaluation was performed. RESULTS: No complications with respect to the combination of implant insertion and mandibulotomy were observed either during or after surgery. In addition, no adverse mucosal reactions were observed during the course of radiotherapy, no cases of osteoradionecrosis developed, and no implants were lost. Clinical and radiographic evaluation revealed healthy peri-implant parameters. CONCLUSION: From this study it is concluded that, when following the technique described, a mandibulotomy can be combined safely with the insertion of implants in the ventral part of the edentulous mandible.

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PubMed2003

Microradiography to evaluate bone growth into a rat mandibular defect.

Microradiography has been evaluated to measure bone healing into a 5.0mm outer diameter mandibular defect in the rat. This method provides high-resolution radiographs of the defects that can be used for an accurate measurement of bone defect healing. In 12 rats, the defect widths of 42-day-old mandibular defects have been measured both using microradiographs and histological sections. The defect width+/-S.D. measured 3.42+/-0.98 mm microradiographically and 3.47+/-1.11 mm histologically. Both methods were accurate in determining defect widths but microradiography has the advantage over histology that an image is obtained from the entire defect, making it possible to measure areas of bone growth.

Animals↗

PubMed2003

Satisfaction and psychosocial aspects of patients with an extremely resorbed mandible treated with implant-retained overdentures. A prospective, comparative study.

The objective of the present report was to study the effect of implant treatment on subjective parameters in edentulous patients with an extremely resorbed mandible. Three different treatment modalities to support an overdenture were compared: transmandibular implant according to Bosker, augmentation of the mandible followed by four endosseous implants, and the insertion of four short endosseous implants. Sixty patients [50 women and 10 men, mean (+/- SD) age 59 (+/- 11) years] met the inclusion criteria and were assigned in one of the three treatment groups. Before treatment and 12 months after placement of the new overdentures, denture satisfaction, psychosocial aspects and experiences during the surgical phase were assessed with a battery of questionnaires. After 1 year, 58 patients were available for evaluation: one patient had died, and one patient had moved out of the region. There was a significant improvement of patient satisfaction and psychosocial functioning in all three treatment groups. At the 1-year evaluation, differences amongst the three groups were not significant. However, in terms of discomfort and pain during the surgical phase as well as the length of this phase (at least 6 months), the augmentation using an autologous bone graft from the iliac crest followed by inserting four endosseous implants 3 months later appeared the least favorite option of the three modalities studied.

Alveolar Ridge Augmentation↗

PubMed2003

Maxillary sinus floor elevation surgery. A clinical, radiographic and endoscopic evaluation.

Although augmentation of the maxillary sinus floor with autogenous bone grafts has become a well established preimplantology procedure, its effect on the function of the maxillary sinus has not been the subject of prospective human studies. In this prospective study the effects of sinus floor augmentation on maxillary sinus performance were evaluated. Seventeen consecutive patients who were to undergo augmentation of the maxillary sinus floor with an iliac crest autogenous bone graft agreed to participate in this study. All patients were subject to (i) extensive anamnestic and clinical investigation on sinusitis, (ii) conventional radiography (Waters' projection) and (iii) unilateral endoscopic inspection of the maxillary sinus. This triad of evaluations was performed preoperatively, immediately preceding the augmentation procedure (the maxillary sinus to be inspected endoscopically was randomly selected), and at 3 (at insertion of the implants) and 9 months (at uncovering of implants) postaugmentation. None of the 17 patients showed clinical or radiological signs of actual sinus pathology preoperatively, though 5 patients had a history of an impeded sinus clearance. By contrast, unilateral endoscopic evaluation revealed pre-existing subclinical mucosal pathology in two out of five patients with a history of sinus clearance impairment and in one out of the other 12 patients. At 3 months' postaugmentation, clinical and radiographical examination showed chronic maxillary sinusitis in one non-compromised patient. Moreover, serial unilateral endoscopic evaluation revealed subclinical maxillary mucosal pathology in four other patients (two of whom had a history of an impeded sinus clearance), confirmed by Waters' projection in three of these four patients. At 9 months' postaugmentation, only subclinical maxillary mucosal pathology was detected endoscopically in two patients (one compromised, one non-compromised patient), confirmed by Waters' projection in this last patient. Five implants were lost during the 9-month observation period. As is obvious from this prospective evaluation, the effects of the augmentation procedure on maxillary sinus performance in patients without signs of maxillary sinusitis are of no clinical significance.

Adult↗