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B Stegenga

Publications and source records attributed to B Stegenga.

At least 19 recordsLinked to original sources
PubMed2006

A long-term in vitro biocompatibility study of a biodegradable polyurethane and its degradation products.

The biological safety of degradation products from degradable biomaterials is very important. In this study a new method is proposed to test the cytotoxicity of these degradation products with the aim to save time, laboratory animals, and research funds. A biodegradable polyurethane (PU) foam was subjected to this test method. The PU had soft segments of DL-lactide/epsilon-caprolactone and hard segments synthesized from butanediol and 1,4-butanediiosocyanate. Copolymer foams without urethane segments, consisting of DL-lactide/epsilon-caprolactone, were tested as well. Accumulated degradation products were collected by degrading the foams in distilled water at 60 degrees C up to 52 weeks. Cell-culture medium was prepared from powder medium with this water. In different tests the cytotoxicity of this medium was established. The first signs of cytotoxicity were observed after 3-5 weeks of degradation. This accounts for both materials and reestablishes the good short-term biocompatibility of these materials. The PU showed more toxicity toward the end stages of degradation in comparison with the copolymer. This is probably related to the accumulation of degradation products of the urethane segments. In the in vivo situation the degradation of the PU and the metabolism and excretion of degradation products may differ. Therefore, long-term in vivo studies will have to establish whether these in vitro results are representative for the in vivo behavior of the degrading PU.

Absorbable Implants↗
PubMed2005

Short-term in vitro and in vivo biocompatibility of a biodegradable polyurethane foam based on 1,4-butanediisocyanate.

In this study short-term in vitro and in vivo biocompatibility apects of a biodegradable polyurethane (PU) foam were evaluated. The PU consists of hard urethane segments and amorphous soft segments based on a copolyester of dl-lactide and epsilon-caprolactone. The urethane segments are of uniform length and synthesized with 1,4-butanediisocyanate. The foam has good mechanical properties and will be used for tissue regeneration applications. Degradation tests were carried out in a buffer solution for twelve weeks. Cytotoxicity was determined using extract and direct contact test methods with incubation periods varying form 24 to 72 h. The foam was implanted subcutaneously for one, four and twelve weeks and the tissue response to the material was histologically evaluated. In vitro, the mass loss was 3.4% after twelve weeks. In the cytotoxicity tests the PU caused no abnormal growth behaviour, nor morphological changes or inhibition in metabolic activity. The in vivo studies showed no toxic tissue response to the PU. Connective tissue ingrowth, accompanied by vascular ingrowth was complete at twelve weeks. In vivo degradation had started within four to twelve weeks. In conclusion, the PU shows a good in vitro and in vivo biocompatibility in these short-term experiments.

Absorbable Implants↗
PubMed2005

Function impairment and pain after closed treatment of fractures of the mandibular condyle.

BACKGROUND: To determine the prognosis of fractures of the mandibular condyle after closed treatment. METHODS: Patients (n = 144) with a fracture of the mandibular condyle, all treated closed, were included in the study. Fracture types and position of the fracture parts were determined on radiographs. Follow-up was after 12 months in which the average pain, experienced during the last week (visual analog scale, 100 mm), and mandibular functioning were assessed (mandibular function impairment questionnaire (MFIQ)). RESULTS: Data of 116 (81%) patients, 41 women (35%) and 75 men (65%), were available for analysis. Condylar neck fractures were most common (52%). Bilateral fractures were present in 28% of the patients. Pain (visual analog scale score >0) was found in 9% of the patients. Impaired mandibular function was found in 40% (MFIQ >0) and 24% (MFIQ > or =4) of the patients. The most important risk factor for pain was being a woman. The most important risk factors for function impairment were > or =25 years of age and gross displacement of the fracture parts. CONCLUSION: The overall prognosis of mandibular function and pain after closed treatment of condylar fractures is good. The most important risk factor for pain persisting for 1 year after closed treatment of a condylar fracture is being a woman. The most important risk factors for function impairment are an age of > or =25 years and gross displacement of the fracture parts.

Age Factors↗
PubMed2005

Masticatory function in patients with an extremely resorbed mandible restored with mandibular implant-retained overdentures: comparison of three types of treatment protocols.

The objective of the present study was to analyse the effects of implant supported overdentures on masticatory function in patients with an extremely resorbed mandible, and to compare the masticatory function in these patients using three differing types of implant treatment protocols. The mandibular overdentures were retained by a transmandibular implant, by four endosseous implants following augmentation of the mandible, and by four short endosseous implants, respectively. Sixty patients (50 women, 10 men, mean age 59.4 years) were randomly allocated to one of the three treatment groups. Masticatory function was assessed before and after treatment using a questionnaire, a masticatory performance test, and a structured interview. The patient-based masticatory function improved significantly. Concerning these parameters there were no significant differences between the three groups before and after treatment. A significant difference existed between the three groups for the laboratory-assessed masticatory function before treatment, but after treatment this difference was no longer significant. From this study it can be concluded that patients with an extremely resorbed mandible and functional complaints of their lower denture report significant improvement in masticatory function after implant-overdenture treatment. Differences in masticatory function between the three studied modalities were not significant after treatment.

Aged↗
PubMed2005

An animal model for oroantral communications: a pilot study with Göttingen minipigs.

A pilot study was performed to investigate whether the Göttingen minipig is a suitable animal model for creating and closing oroantral communications (OACs) and to test whether these defects can be closed with a biodegradable polyurethane (PU) foam. In three adult minipigs, an OAC was created on both sides of the maxilla. The left side was closed by a standard surgical buccal flap procedure, the right side by applying a PU foam. The pigs were killed after two weeks, one month and three months, respectively. Postmortem and histological examination showed that an OAC was created in only one of six cases. In the remaining cases, the infraorbital canal was perforated instead of the floor of the maxillary sinus. It was concluded that the Göttingen minipig is not a suitable animal model for OAC investigations. As a result, the closure of OACs with a biodegradable PU could not be evaluated.

Animals↗
PubMed2005

[Trigeminal neuralgia by an acoustic neuroma. The need of imaging].

In a 43-year old female with neuralgia of the second and third branch of the trigeminal nerve, the diagnosis was made on the basis of clinical findings. After the patient was treated with 2 x 200 mg of carbamazepine, all initial symptoms resolved, which confirmed the diagnosis. To distinguish between idiopathic and secondary trigeminal neuralgia, magnetic resonance imaging was scheduled. This investigation showed an acoustic neuroma in the cerebellopontine angle. Without magnetic resonance imaging this benign tumour would be diagnosed in a much later stage and the patient would have suffered unnecessary co-morbidity. Due to the relatively high incidence of secondary trigeminal neuralgia, routine magnetic resonance imaging in patients with a trigeminal neuralgia is justifiable.

Adult↗
PubMed2004

Efficacy and co-morbidity of oral appliances in the treatment of obstructive sleep apnea-hypopnea: a systematic review.

The Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) is a common sleep-related breathing disorder characterized by repetitive obstructions of the upper airway during sleep. Modification of pharyngeal patency by Oral Appliance (OA) therapy has been suggested as an alternative to various treatment modalities for OSAHS. To determine the evidence base with respect to the efficacy and co-morbidity of OA therapy in OSAHS, we conducted a systematic review of the available literature. Primary outcome measures were the reduction in number of upper-airway obstructions and co-morbidity related to the craniomandibular or craniofacial complex, respectively. Eligible studies regarding efficacy were independently assessed by two assessors using a quality assessment scale. Effect sizes of methodologically sound studies were calculated. In identical interventions, effect sizes were pooled with the use of a random-effects model. Given the scarcity of controlled studies related to co-morbidity, appraisal was confined to a description of eligible studies. Sixteen controlled trials related to efficacy were identified. With respect to the primary outcome measure, OA therapy was clearly more effective than control therapy (pooled effect size, -0.96; 95% confidence interval [CI], -1.49 to -0.42) and possibly more effective than uvulopalatopharyngoplasty. Although patients generally preferred OA therapy, improvement of respiratory variables, such as the number of upper-airway obstructions, was usually better in Continuous Positive Airway Pressure (CPAP) therapy (pooled effect size, 0.83; 95% CI, 0.59 to 1.06). Moreover, specific aspects related to OA design may influence patient-perceived efficacy and preference. Twelve patient-series and one controlled trial related to co-morbidity were identified. Analysis of the data suggests that OA therapy may have adverse effects on the craniomandibular and craniofacial complex. Although CPAP is apparently more effective and adverse effects of OA treatment have been described, it can be concluded that OA therapy is a viable treatment for, especially, mild to moderate OSAHS. Controlled studies addressing the specific indication and co-morbidity of OA therapy are warranted.

Comorbidity↗
PubMed2004

[Vicryl Rapide versus Safil Quick. A prospective comparison of two fast resorbing suturing materials].

Currently, there are two fast-resorbing suturing materials on the Dutch market, viz. Vicryl Rapide and Safil Quick. The aim of this study was to compare the clinical suitability of both suturing materials, which was defined as minimal discomfort or pain for the patient, good knot security and tensile strength, predictable resorption, minimal tissue response, and good wound healing. In a group of 120 patients (60 patients randomized in each group), who were referred for apectomy, the clinical suitability of Vicryl Rapide and Safil Quick as fast-resorbing suturing materials was prospectively studied. The results showed that the tested materials were equivalent with regard to most aspects of their clinical suitability.

Absorption↗
PubMed2004

[Nerve injury during mandibular third molar surgery. The importance of preoperative diagnosis and surgical skill].

A 26-year-old woman was referred by a dentist to an oral and maxillofacial surgeon after an unsuccessful attempt to remove a mandibular third molar. A panoramic radiograph showed the remaining root of the third molar and the patient suffered from insensitivity of the lower lip. The root of the third molar was removed surgically. The sensitivity of the lip recovered completely within three months. Injury of the inferior alveolar nerve and the lingual nerve is a serious complication after mandibular third molar removal. The inferior alveolar nerve is at risk for injury if the third molar root is intimately connected with the mandibular canal. Refraining from preoperative clinical and radiographic diagnostics is malpraxis. Surgical skill is a prerequisite to reduce the risk of nerve injury.

Adult↗
PubMed2004

[Root canal retreatment or surgical apicoectomy?].

Failure of root canal therapy is usually due to re-infection of the root canal system. In most of these cases, an endodontic retreatment is indicated. Patients with persisting apical periodontitis frequently are referred to an oral surgeon for apical surgery, although endodontic retreatment would have been possible in a majority of these cases. When endodontic retreatment is not possible or does not resolve the patient's problems, surgical apicoectomy or extraction might be the only possibilities left. Apical surgery is usually performed by an oral sugeon or by a specially trained dentist. In most surgical clinics beveled resection, followed by an preparation and restoration is performed. New developments, such as microscopic sugery, ultrasonic preparation and newly developed restorative materials are described in this article. Since there is a lack of well-designed comparative clinical studies, no definite conclusions can be drawn with regard to the clinical value of these modern techniques.

Apicoectomy↗
PubMed2003

Craniofacial morphology and obstructive sleep apnoea: a cephalometric analysis.

The craniofacial morphology of 31 male patients diagnosed with obstructive sleep apnoea syndrome (OSAS) and 37 healthy male subjects were compared using cephalometric evaluation of lateral skull radiographs. The aim was to evaluate which cephalometric variables related to craniofacial morphology discriminate between OSAS patients and non-OSAS subjects. Sixteen cephalometric measurements were determined to study the craniofacial morphology. Differences in cephalometric variables between the two groups were analysed with unpaired Student t-tests (significance level 0.05). A multiple regression analysis was used to evaluate the joint predictive value of selected variables. With regard to five variables, significant differences were observed between OSAS patients and non-OSAS subjects (P < 0.05). Data indicated a relatively anterior position of the maxilla, an increase of the mid-facial height and a more inferiorly located hyoid bone in the OSAS patient group. The multiple regression analysis yielded a model discriminating between OSAS patients and non-OSAS subjects, which included two hyoid bone variables and one related with the intermaxillary relationship. A causal relationship between cephalometric variables of craniofacial morphology and OSAS is not sufficiently supported by our data. Presumably, hyoid bone position is of predictive value in the cephalometric discrimination between OSAS patients and non-OSAS subjects.

Adult↗
PubMed2003

Ultrasound stimulation of maxillofacial bone healing.

A substantial part of the maxillofacial surgery practice deals with maxillofacial bone healing. In the past decades, low-intensity ultrasound treatment has been shown to reduce the healing time of fresh fractures of the extremities up to 38%, and to heal delayed and non-unions up to 90% and 83%, respectively. Based on the assumption that the process of bone healing in the bones of the extremities and maxillofacial skeleton is essentially the same, the potential of ultrasound to stimulate maxillofacial bone healing was investigated. Although limited evidence is available to support the susceptibility of maxillofacial bone to the ultrasound signal, ultrasound may be of value in the treatment of delayed unions, in callus maturation after distraction, and in the treatment of osteoradionecrosis.

Animals↗
PubMed2003

A randomized prospective clinical trial on the effectiveness of three treatment modalities for patients with lower denture problems. A 10 year follow-up study on patient satisfaction.

Treatment of lower denture complaints of patients with an edentulous mandible with a height of at least 15 mm can consist of meticulous construction of a new set of dentures (CD), construction of a new set of dentures following preprosthetic surgery to enlarge the denture-bearing area (PPS), or construction of an implant-retained mandibular overdenture (IRO). The aim of this prospective randomized controlled clinical trial was to evaluate the satisfaction of the above mentioned treatment modalities in resolving lower denture related complaints. Ninety edentulous patients (Cawood class IV and V, mean mandibular height 20.7 +/- 2.7 mm) were randomly assigned to one of these treatment modalities. The main outcome parameters were denture satisfaction and chewing ability, which were assessed using validated self-administered questionnaires focusing on denture-related complaints and problems with chewing different types of food. These parameters were measured before treatment, and 1, 5 and 10 years after treatment. Differences among the three groups were tested by applying a one way analysis of variance and a Tukey's test for multiple comparison. At the 1 year evaluation, significantly better scores were observed in the two surgical groups (IRO, PPS) than in the CD group (P<0.05). At 5 year evaluation the 'complaints of the lower denture' showed a significantly better score in the IRO group when compared to the PPS and CD groups (P<0.05). No significant differences were observed between the PPS and CD group. At 10 year evaluation, the intention to treat analysis revealed no significant differences between the three groups, while a per protocol analysis showed that the IRO group was the most satisfied. From this study it is concluded that both on the short and long term denture satisfaction appears most favourable in the IRO group when compared to the PPS and CD groups. Implant-retained overdentures are, therefore, a favourable treatment modality for edentulous patients with lower denture problems.

Adult↗
PubMed2002

Groningen temporomandibular joint prosthesis. Development and first clinical application.

Patients with a severely degenerated temporomandibular joint (TMJ) may benefit from an alloplastic TMJ replacement. The aim of the study was to develop a safe and properly functioning TMJ prosthesis. The design was based on imitation of anterior condylar translation by an inferiorly located centre of rotation, unrestricted mandibular movements by a double articulation, correct fit to the skull by a self-adjusting skull part consisting of two connected parts, and stable fixation by bone screws that are rigidly connected to the prosthesis parts. The prosthesis consists of a titanium skull part with ceramic inlay, a titanium mandibular part with a ceramic spherical head, and an intervening polyethylene disc. Titanium-alloy bone screws are used for fixation. All parts are available in a number of different shapes. In vitro laboratory and in vivo animal tests showed a low wear rate, the possibility of a close fit to the skull, a stable fixation, sufficient mechanical strength, appropriate choice of materials and proper functioning. Thereafter the step to first patient application was made. First patient application was carried out without adverse events. In conclusion, the presented TMJ prosthesis passed the pre-clinical tests and has progressed to clinical application. The fit to the skull, the expected lifetime of the device and the reliability of the implantation procedure require further evaluation in well-designed clinical trials.

Adult↗
PubMed2002

Sialometry and sialochemistry: a non-invasive approach for diagnosing Sjögren's syndrome.

BACKGROUND: Analysis of salivary variables has frequently been proposed as a diagnostic tool for Sjögren's syndrome (SS). Because univocal salivary reference values are lacking, it is currently rather difficult to use sialometry and sialochemistry for diagnosing SS unless major changes have occurred in salivary secretion and composition. OBJECTIVE: To define reference values of several salivary variables, which offer a possible new and non-invasive means of diagnosing SS. METHODS: Cut off points were selected from receiver operating characteristic curves of gland-specific sialometrical and sialochemical variables, which have proved to be potentially relevant for diagnosing SS in a previous study-that is, sodium, chloride, and phosphate concentration in stimulated parotid and submandibular/sublingual (SM/SL) saliva, unstimulated and stimulated SM/SL flow rates, and lag phase of parotid secretion, respectively. By combining the most discriminating variables, two different diagnostic approaches for SS were applied in a group of 100 patients and subsequently evaluated in a second group of 20 patients. The first approach was to combine variables by applying their cut off points into sets of criteria for a positive diagnosis of SS. The second approach was to construct a logistic regression model that predicts the true state of a patient (SS or non-SS). From both approaches, the tests with highest likelihood ratio combined with the smallest number of rejected cases were selected for clinical use. RESULTS: The most accurate test combined the stimulated SM/SL flow rate and parotid sodium and chloride concentration as salivary variables for diagnosing SS; it had a sensitivity of 0.85 and a specificity of 0.96. The selected tests proved equally accurate in the second group of patients. CONCLUSIONS: Because the proposed non-invasive diagnostic tools can be easily applied, do not need a laboratory other than for routine blood testing, and are very accurate, gland-specific sialometry and sialochemistry may eventually replace other, more invasive, diagnostic techniques for diagnosing SS.

Adult↗
PubMed2002

The association between generalized joint hypermobility and temporomandibular joint disorders: a systematic review.

To analyze conflicting evidence in the literature for the association between temporomandibular joint disorders (TMD) and generalized joint hypermobility (GJH), we performed a bibliographic search. The methodological quality of the 14 papers found was assessed according to 14 criteria. Papers were included in the analysis if the study population was clinically relevant, if range of motion of 2 or more joints was assessed on the left and right sides, and if cases had a TMD. Four studies fulfilled these selection criteria. Data from 3 studies, 113, cases and 95 controls, were available for analysis. Twenty-six cases and five controls were hypermobile (odds ratio, 5.4). In a sensitivity analysis, the odds ratio changed from significant to non-significant in 2 of 5 scenarios. As a result, it is not clear whether GJH is associated with TMD, and more rigorous studies are needed.

Adult↗
PubMed2001

Maxillary bone grafting for insertion of endosseous implants: results after 12-124 months.

Insertion of endosseous implants in the atrophic maxilla is often complicated because of lack of supporting bone. Augmentation of the floor of the maxillary sinus with autogenous bone graft has been proven to be a reliable treatment modality, at least in the short term. The long-term clinical and radiographic outcome with regard to the grafts, the implants and satisfaction of the patients with their implant-supported overdenture was studied in 99 patients. The sinus floor was augmented with bone grafts derived from the iliac crest (83 subjects, 162 sinuses, 353 implants), the mandibular symphysis (14, 18, 37), or the maxillary tuberosity (2, 2, 2). Before implant installation, the width and height of the alveolar crest were increased in a first stage procedure in 74 patients, while in the other 25 patients augmentation and implant installation could be performed simultaneously (width and height of the alveolar crest >5 mm). Perforation of the sinus membrane occurred in 47 cases, which did not predispose to the development of sinusitis. Loss of bone particles and sequestration were observed in one (diabetic) patient only, in whom a dehiscence of the oral mucosa occurred. A second augmentation procedure was successful in this patient. Symptoms of transient sinusitis were observed in 3 patients. These symptoms were successfully treated with decongestants and antibiotics. 2 other patients developed a purulent sinusitis which resolved after a nasal antrostomy. In all cases, the bone volume was sufficient for implant insertion. 32 of 392 inserted Brånemark implants (8.2%) were lost during the follow-up. After the healing period of the bone grafts, no sinus pathology was observed. The patients received implant-supported overdentures (72 patients) or fixed bridges (27 patients). Overall, the patients were very satisfied with the prosthetic construction. We conclude that bone grafting of the floor of the maxillary sinus floor with autogenous bone for the insertion of implants is a reliable treatment modality with good long-term results.

Adolescent↗