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Biomedical subjects

Arjan Vissink

Publications and source records attributed to Arjan Vissink.

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.

Aged↗
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↗
PubMed2005

Radioprotective effect of amifostine on parotid gland functioning is region dependent.

PURPOSE: To investigation the protective ability of amifostine during partial irradiation of the rat parotid gland. METHODS AND MATERIALS: Single-dose X-ray irradiation was performed by use of collimators with conformal radiation portals for either the 100% volume (15 Gy) or the 50% cranial/caudal partial parotid gland volumes (30 Gy). Amifostine was administered intraperitoneally at a dose of 250 mg per kg body weight, 25 minutes before irradiation. Saliva flow rates, gland weights, and the tissues of the individual lobes were investigated up to 1 year after treatment. RESULTS: A clear protective effect of amifostine was found against loss of saliva flow, the altered appearance of gross morphology, loss of gland weight, and histopathologic changes for the 100% volume gland irradiations and for the 50% volume cranial irradiations but not for the 50% volume caudal irradiations. CONCLUSIONS: The protective ability of amifostine is strongly dependent on the irradiated glandular region and observed for later damage only. The major effect of the drug seems to be the prevention of volume effects caused by secondary damage that occurs in shielded parts of the gland. The results of the present study show that understanding of the anatomy and physiology of organs that are to be spared is necessary to ensure optimal preservation of function.

Amifostine↗
PubMed2005

Secondary radiation damage as the main cause for unexpected volume effects: a histopathologic study of the parotid gland.

PURPOSE: To elucidate with a histopathological study the mechanism of region-dependent volume effects in the partly irradiated parotid gland of the rat. METHODS AND MATERIALS: Wistar rats were locally X-irradiated with collimators with conformal radiation portals for 100% volume and 50% cranial/caudal partial volumes. Single doses up to 40 Gy were applied. Parotid saliva samples were collected, and the three lobes of the parotid gland were examined individually on the macro- and micromorphologic level up to 1 year after irradiation. RESULTS: Dose-dependent loss of gland weight was observed 1 year after total or partial X-irradiation. Weight loss of the glands correlated very well with loss of secretory function. Irradiating the cranial 50% volume (implicating a shielded lateral lobe) resulted in substantially more damage in terms of weight loss and loss of secretory function than 50% caudal irradiation (shielding the ventral and dorsal lobe). Histologic examinations of the glands 1 year after irradiation revealed that the shielded lateral lobe was severely affected, in contrast to the shielded ventral and dorsal lobes. Time studies showed that irradiation of the cranial 50% volume caused late development of secondary damage in the shielded lateral lobe, becoming manifest between 240 and 360 days after irradiation. The possible clinical significance of this finding is discussed. CONCLUSION: It is concluded that the observed region-dependent volume effect for late function loss in the rat parotid gland after partial irradiation is mainly caused by secondary events in the shielded lateral lobe. The most probable first step (primary radiation event) in the development of this secondary damage is radiation exposure to the hilus region (located between the ventral and dorsal lobe). By injuring major excretory ducts and supply routes for blood and nerves in this area, the facility system necessary for proper functioning of the nonexposed lateral lobe is seriously affected. The unexpected volume effect in the rat might have consequences for treatment strategies in radiotherapy, implicating not only salivary glands but also other organs with a seemingly homogeneous distribution of radiosensitive elements, a situation wherein volume effects have not been anticipated up to now.

Animals↗
PubMed2005

On the mechanism of salivary gland radiosensitivity.

PURPOSE: To contribute to the understanding of the enigmatic radiosensitivity of the salivary glands by analysis of appropriate literature, especially with respect to mechanisms of action of early radiation damage, and to supply information on the possibilities of amelioration of radiation damage to the salivary glands after radiotherapy of head-and-neck cancer. METHODS AND MATERIALS: Selected published data on the mechanism of salivary gland radiosensitivity and radioprotection were studied and analyzed. RESULTS: From a classical point of view, the salivary glands should not respond as rapidly to radiation as they appear to do. Next to the suggestion of massive apoptosis, the leakage of granules and subsequent lysis of acinar cells was suggested to be responsible for the acute radiation-induced function loss of the salivary glands. The main problem with these hypotheses is that recently performed assays show no cell loss during the first days after irradiation, while saliva flow is dramatically diminished. The water secretion is selectively hampered during the first days after single-dose irradiation. Literature is discussed that shows that the compromised cells suffer selective radiation damage to the plasma membrane, disturbing signal transduction primarily affecting watery secretion. Although the cellular composition of the submandibular gland and the parotid gland are different, the damage response is very alike. The acute radiation-induced function loss in both salivary glands can be ameliorated by prophylactic treatment with specific receptor agonists. CONCLUSIONS: The most probable mechanism of action, explaining the enigmatic high radiosensitivity for early effects, is selective radiation damage to the plasma membrane of the secretory cells, disturbing muscarinic receptor stimulated watery secretion. Later damage is mainly due to classical mitotic cell death of progenitor cells, leading to a hampered replacement capacity of the gland for secretory cells, but is also caused by damage to the extracellular environment, preventing proper cell functioning.

Animals↗
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.

Aged↗
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

Variability of flow rate when collecting stimulated human parotid saliva.

The aim of this study was to estimate the accuracy and reproducibility of citric-acid-stimulated parotid saliva sampling. In healthy volunteers a strong correlation (r2 = 0.79) between flow rates from the left and right parotid gland was observed. In patients with Sjögren's syndrome this correlation (r2 = 0.90) was even stronger. The intraindividual variation in healthy volunteers was 23.3 +/- 5.9%. Increasing the number of collections did not reduce this variation significantly. In head and neck cancer patients, to estimate whether repeated measurements result in more reliable baseline values for use in clinical studies, repeated collections did not result in a significant reduction of intrapatient variation, similar to the results with the healthy volunteers. Thus, notwithstanding the good agreement between left and right flow rates, a high variation in parotid flow rates has to be considered when planning clinical trials evaluating the effects of treatment on salivary gland functioning.

Adult↗
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

Comparison of lacrimal and salivary gland involvement in Sjögren's syndrome.

OBJECTIVES: To determine the performance of different tear and salivary tests applied in Sjögren's syndrome (SS) and to disclose how these tests relate to common serologic tests in SS. DESIGN: In addition to the routine ocular and oral tests for diagnosing SS (Schirmer test, rose bengal score, unstimulated whole saliva flow, and parotid sialography), tear breakup time and flow rate of glandular saliva (parotid and submandibular-sublingual [SM/SL]) were evaluated in patients referred for diagnosis of SS. Patients were categorized into primary SS, secondary SS, and non-SS groups according to the revised European classification criteria for SS. SETTING: Referral center. PATIENTS: Referred sample of 80 consecutive patients. MAIN OUTCOME MEASURE: Correlation between ocular and salivary measures. RESULTS: Breakup time performed insufficiently in diagnosing SS, as opposed to the rose bengal score. In patients with primary and secondary SS, a clear correlation was noted between tear and saliva quality and secretion rate, and between the rose bengal score and parotid sialography. Increased rose bengal scores also correlated significantly with hyperglobulinemia and presence of SS-B antibodies in serum, with duration of subjective eye dryness, and with decreased tear-gland function. With regard to the oral tests, whole, parotid, and SM/SL salivary flow decreased significantly with increasing duration of oral complaints, with the stimulated SM/SL flow rate showing the strongest decrease and being more specific in diagnosing SS. Also, parotid sialography was more specific in excluding patients without SS than the commonly applied diagnostic criterion of secretion of unstimulated whole saliva. CONCLUSIONS: The rose bengal score remains the eye test of choice, as it has the highest specificity for SS. Hyperglobulinemia and especially positive serologic findings for SS-B may warrant close monitoring of the eyes, since these serum findings appear to relate to the severity of ocular surface damage. Parotid sialography and stimulated secretion of SM/SL saliva are more specific in diagnosing SS than unstimulated secretion of whole saliva.

Antibodies↗
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.

Aged↗
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↗
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↗
PubMed2002

Detection of unknown primary tumours and distant metastases in patients with cervical metastases: value of FDG-PET versus conventional modalities.

In 1%-2% of head and neck oncology patients, the only symptom of a malignancy is a positive cervical node. The aim of this study was to compare the value of positron emission tomography using fluorine-18 fluoro-2-deoxy- D-glucose (FDG-PET) and conventional diagnostic modalities (CT and/or MRI, panendoscopy) in detecting unknown primary tumours and distant metastases in patients suffering from such a cervical metastasis. Fifty patients (37 men and 13 women) with cervical metastases of an unknown primary tumour were included. All patients underwent FDG-PET. In addition, CT and/or MRI was obtained and panendoscopy was performed. All clinically known metastases were detected by FDG-PET. The primary tumour could be diagnosed in 16 patients (four primary tumours were detected exclusively by FDG-PET). Seven patients had multiple distant metastases, that in six cases were detected exclusively by FDG-PET. The sensitivity and specificity of FDG-PET for detection of unknown primary tumours were 100% and 94%, respectively. For the conventional diagnostic modalities these values were 92% and 76%. FDG-PET had an exclusive effect on the applied therapy in 20% of the patients referred for diagnosis of an unknown primary tumour. The data obtained in this study strongly support the diagnostic strategy of performing FDG-PET in patients suffering from cervical metastases of an unknown primary tumour before any other diagnostic technique.

Adenocarcinoma↗