Biomedical subjects

Henny J A Meijer

Publications and source records attributed to Henny J A Meijer.

At least 19 recordsLinked to original sources

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.

Aged↗

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

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

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

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

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

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

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

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

Posterior mandibular residual ridge resorption in patients with conventional dentures and implant overdentures.

PURPOSE: This study investigated the effects of certain systemic and local factors on resorption of the posterior mandibular residual ridge under conventional dentures and overdentures supported by 2 implants. MATERIALS AND METHODS: Proportional area measurements of the posterior mandible were made on rotational tomograms taken immediately before and 5 years after treatment. The area was bounded by a line joining gonion to the lowest point of the mental foramen and the crest of the residual ridge and was expressed as a proportion of an area that was not dependent on the ridge. The use of proportions rather than actual measurements minimized errors related to magnification and distortion. RESULTS: The estimated average reduction in height was 1.25 mm in 5 years (1.63 mm for conventional denture groups and 0.69 mm for implant overdenture groups, ie, almost 1 mm less in the overdenture group). DISCUSSION AND CONCLUSION: Female gender was a risk factor for greater resorption. Other factors, such as the number of years a patient had been edentulous, initial height of the mandible, and the number of dentures used, failed to show an association with resorption of the residual posterior mandibular ridge, while the statistically significant effect of age was unlikely to be clinically significant.

Adult↗

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

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↗