Andries Van Der Bilt - Academia.edu (original) (raw)
Papers by Andries Van Der Bilt
Archives of Oral Biology, 2007
Journal of Cranio-Maxillofacial Surgery, 2015
Segmental resection of the mandible causes functional, aesthetic and social problems affecting he... more Segmental resection of the mandible causes functional, aesthetic and social problems affecting health-related quality of life (HRQoL). It is often assumed that reconstruction with composite free flaps guarantees better function and aesthetics than bridging the defect with reconstruction plates. Using the European Organization for Research and Treatment of Cancer questionnaires (EORTC QLQ-C30 version 3.0 and EORTC QLQ-H&N35), we compared HRQoL in patients who received free fibula flaps versus reconstruction plates after segmental resection of the lateral mandible. Thirty-seven completed questionnaires (18 fibula reconstructions and 19 patients with reconstruction plates) were available. Reconstruction with a free fibula flap did not provide clear additional benefit to bridging the defect with a reconstruction plate after segmental resection of the lateral mandible. In particular aspects known to have the most impact on HRQoL like swallowing, speech and chewing were not influenced by the type of reconstruction. Reconstruction of segmental defects of the lateral mandible with free fibula flap and reconstruction plate resulted in comparable HRQoL. If dental rehabilitation by means of dental implants is not anticipated in the fibula, then plate reconstruction with adequate soft tissue remains a suitable technique for the reconstruction of segmental defects of the lateral mandible.
Journal of child neurology, Jan 19, 2015
Duchenne muscular dystrophy patients report masticatory problems. The aim was to determine the ef... more Duchenne muscular dystrophy patients report masticatory problems. The aim was to determine the efficacy of mastication training in Duchenne muscular dystrophy using chewing gum for 4 weeks. In all, 17 patients and 17 healthy age-matched males participated. The masticatory performance was assessed using a mixing ability test and measuring anterior bite force before, shortly after and 1 month after the training. In the patient group the masticatory performance improved and remained after 1-month follow-up, no significant changes in anterior maximum bite force was observed after mastication training. In the healthy subject the bite force increased and remained at the 1-month follow-up; no significant differences in masticatory performance were observed. Mastication training by using sugar-free chewing gum in Duchenne muscular dystrophy patients improved their masticatory performance. Since bite force did not improve, the working mechanism of the improvement in chewing may relate to cha...
International journal of oral and maxillofacial surgery, 2007
A simple, modified method to evaluate changes in the nasolabial soft tissues after orthognathic s... more A simple, modified method to evaluate changes in the nasolabial soft tissues after orthognathic surgery is presented. Eighteen healthy volunteers were photographed in a standardized manner with a 2-month interval. Pictures were taken with the soft tissues in repose and 'maximum closed mouth smile'. Discrepancies for repose and dynamic excursions (x and y coordinates) were calculated for the landmarks alare, crista philtri and cheilion. Multiple analysis of variance revealed no significant interaction for intra-observer variance and time of recording. Coefficients of reliability (repose: 90-99%, dynamic excursion (cheilion): >95%), Spearman correlation coefficients (repose: >0.8, dynamic: >0.6) and squared correlation (repose: >75%, dynamic: >50%) showed this method to be reliable for repose and dynamic excursions. The error of measurement was less than 1.8 mm for both repose and dynamic excursions (SD(differences)=0.9 mm). This is smaller than mean differences...
Nederlands tijdschrift voor tandheelkunde, 2006
The purpose of this study was to determine patient satisfaction with implant supported mandibular... more The purpose of this study was to determine patient satisfaction with implant supported mandibular overdentures using magnet, bar-clip and ball-socket attachments, and to assess the relation between maximum bite force and patient satisfaction. In a crossover clinical trial, 18 edentulous patients with lower denture complaints received 2 mandibular implants and new lower and upper dentures. The lower denture initially came without any kind of attachment system, but was fitted with one of the attachment types after 3 months. The attachments were changed 3 months thereafter, in random order. A questionnaire concerning denture complaints was given at baseline (with the old denture), after 3 months of functioning with the new denture without attachments and after 3 months of functioning with each of the attachments (within-subject comparison). In addition, at the end of the experiment patients were asked to express their overall satisfaction with their dentures on a visual analogue scale ...
Physiology and Behavior, 2003
Physiology & Behavior, 2006
The production of sufficient saliva is indispensable for good chewing. Recent research has demons... more The production of sufficient saliva is indispensable for good chewing. Recent research has demonstrated that salivary flow rate has little influence on the swallowing threshold. We examined the hypothesis that adding fluid to a food will influence the chewing process. Twenty healthy subjects chewed on melba toast, breakfast cake, carrot, peanut and Gouda cheese. In addition they chewed on these foods after we added different volumes of tap water or a solution of alpha-amylase. We measured jaw muscle activity and the number of cycles until swallowing. Furthermore, we obtained visual analogue scale (VAS) scores for texture and sound attributes for all foods and fluid conditions. The additional fluids significantly lowered muscle activity and swallowing threshold for melba, cake and peanut. The effect of alpha-amylase in the solutions was rather limited. Doubling the volume of tap water had a larger effect. Several texture and sound attributes of melba, cake and peanut were also significantly affected by the additional fluids. For melba, cake, and peanut we observed significant correlations between the physiology parameters and several attributes for the various fluid conditions. This indicates that the added fluid affects both the physiology (muscle activity and number of cycles) and the sensory perception of a number of texture and sound attributes. Adding fluid facilitates the chewing of dry foods (melba, cake), but does not influence the chewing of fatty (cheese) and wet products (carrot).
Physiology & Behavior, 2005
Practically all foods contain particles. It has been suggested that the presence of particles in ... more Practically all foods contain particles. It has been suggested that the presence of particles in food may affect the perception of sensory attributes. In the present study we investigated the effect of size and type (hardness and shape) of particles added to a CMC based vanilla custard dessert. The two types of particles included in the study were silica dioxide and polystyrene spheres, varying in size from 2 -230 µm. Eighteen trained adults participated in the study. They rated the sensation of 18 sensory flavor and texture attributes on a 100 point VAS-scale.
Physiology & Behavior, 2003
The effect of adding saliva or a saliva-related fluid (α-amylase solution and water) to custard p... more The effect of adding saliva or a saliva-related fluid (α-amylase solution and water) to custard prior to ingestion on the sensory ratings of odour, flavour, lip-tooth-feel, mouth-feel and afterfeel sensations was investigated. Saliva had previously been collected from the subjects and each subject received his/her own saliva. Sixteen subjects from a trained panel assessed 17 flavour and texture attributes of soy-and milk-based custard desserts. Immediately prior to administration, two different volumes (0.25 and 0.5 ml) of three different saliva-related fluids (saliva, α-amylase solution and water) were added to the product. The added volumes represented an approximately 33 % and 66 % increase of the volume of saliva present in the mouth during ingestion. The results show that addition of a fluid affected the mouth-feel attributes of melting, thickness and creamy. Melting was the only attribute on which the type of fluid had an effect, where saliva elicited a stronger melting effect than the α-amylase solution and water. The volume of the added fluid affected a number of attributes (thick and creamy mouth-feel and fatty after-feel). It can be concluded that in general the sensory attributes of semi-solids were relatively stable. Mouth and after-feel sensations were partly affected, while odour, flavour, and lip-tooth-feel sensations were not affected by an increase in volume of saliva or other saliva-related fluid during ingestion.
Oral Oncology, 2008
The objective of this study was to determine the value of dynamic contrast-enhanced MRI (DCE-MRI)... more The objective of this study was to determine the value of dynamic contrast-enhanced MRI (DCE-MRI) for the preoperative assessment of mandibular invasion in squamous cell carcinomas (SCC), adjacent or fixed to the mandible. DCE-MRI was performed with gadolinium diethylene triamine pentaacetic acid (Gd-DTPA). Data were obtained from 25 patients. From pharmacokinetic analysis of the tissue uptake of Gd-DTPA, the DCE-MRI parameters (k(ep), K(trans) and v(e)) were determined, with k(ep) representing the exchange rate constant, K(trans) the volume transfer constant and v(e) the volume of extracellular space per unit volume of tissue. The histology of the resection specimens was used as gold standard for the extent of mandibular invasion. SCC with medullary invasion showed higher mean k(ep) and K(trans) compared with SCC without medullary invasion (ANOVA, p<0.001). ROC analysis of k(ep) and K(trans) revealed reliable threshold values for medullary invasion. In conclusion, DCE-MRI can discriminate SCC with medullary invasion from SCC without medullary invasion and may serve as a valuable tool in preoperative tumour staging with regard to the delineation of medullary invasion.
Journal of Texture Studies, 2008
In the oral cavity, the food is subjected to several mechanical and chemical processes. It is fra... more In the oral cavity, the food is subjected to several mechanical and chemical processes. It is fractured by the teeth, diluted and broken down by saliva, heated or cooled by the ambient temperature of the mouth, formed into a bolus and finally swallowed. Numerous receptors in the oral cavity and nose respond to the initially ingested food and monitor the changes during processing. This leads to central perceptions of taste, odor, irritation and texture of the food. Most sensations associated with food texture occur only when the food is manipulated, deformed or moved across the oral receptors. In addition, people assessing the same stimulus differ in their ratings of that stimulus and their oral physiological parameters also exhibit inter-individual variations.
Journal of Texture Studies, 1986
ABSTRACT The masticatory performance of an individual has been quantified by determining the part... more ABSTRACT The masticatory performance of an individual has been quantified by determining the particle sizes of the comminuted food. Optosil, a silicon rubber, has been used as an artificial test food in clinical studies, because it has reproducible textural properties. A comparison between Optosil and several natural foods was made by measuring textural properties of Optosil, turnip, carrot, Gouda cheese and peanut. Several types of probes were used to imitate the cusp form of the teeth. Force-deformation plots revealed similar maximum firmness for Optosil, turnip and carrot, whereas peanut showed a larger firmness. The force needed to crush Optosil is much larger than for the natural foods, but it is well within the physiological range of healthy subjects. The reproducibility of the textural properties is better for Optosil than for the natural foods. The particle size distribution of Optosil broken by a testing machine was compared with the results obtained during chewing.
The Journal of Prosthetic Dentistry, 2011
The aim of this study was to evaluate patient satisfaction and clinical and prosthetic outcomes o... more The aim of this study was to evaluate patient satisfaction and clinical and prosthetic outcomes of two-implant mandibular overdenture treatment with different attachment types after 10 years of function. In a crossover clinical trial, 18 edentulous subjects with complaints regarding their mandibular dentures received two implants and a new denture with magnet, ball-socket, or bar-clip attachments that were applied in a random order. At the end of the experiment, the attachment type of their choosing was fitted in the overdenture. After 10 years, 7 subjects with a ball-socket and 7 subjects with a bar-clip attachment were available for evaluation. The same questionnaire from 10 years before was completed, and subjects were asked to express their overall appreciation of their dentures on a visual analog scale (VAS). Six scales of denture complaints were constructed. Mean scale and VAS scores between initial evaluation and after 10 years were compared. In addition, marginal probing depths, Bleeding Index, and radiographic marginal bone loss were assessed. There was no marked difference in satisfaction between subjects with ball-socket- and bar-clip-retained two-implant mandibular overdentures at initial evaluation and after 10 years of function. Patients' appreciation of their implant-retained denture was and remained high over time. Clinical parameters revealed healthy mucosal conditions and stable marginal bone levels, determined radiographically. Probing depths around implants provided with ball-socket attachments were slightly shallower than those with bar-clip attachments after 10 years of function (P < .05).
Journal of Cranio-Maxillofacial Surgery, 2013
The purpose of this study was to evaluate the use of synthetic bone graft material as a filling m... more The purpose of this study was to evaluate the use of synthetic bone graft material as a filling material at the mandibular symphysis donor site of autologous bone in children. A blinded patient group comprised 20 patients with unilateral (UCLP) or bilateral (BCLP) cleft of lip and palate, all with an indication for alveolar cleft repair. The study took the form of a prospective randomized clinical trial. We used lateral cephalograms for the measurement of the symphyseal donor area defect both peroperatively and at 12 months postoperatively. The data obtained were digitalized and the treatment outcome expressed in numbers. Comparisons with a previous study were made. Histology of biopsies and CT scans were used for visualising bone formation. This study demonstrates that the micro-structured, resorbable calcium phosphate ceramic provides good regeneration properties for the repair of a critical size bony defect in children. One year postoperatively, the measurements taken from lateral cephalograms show that there is scarcely any visible residual defect. Histological investigations of the bone biopsies show solid, induced bone formation and almost complete resorption of the micro-structured calcium phosphate. The findings of this study (novel in children) indicate that micro-structured resorbable calcium phosphate is an excellent alternative to autologous bone. The digital findings showed a restored donor site defect significantly indicating the efficacy (i.e., osteoconductivity and resorbability) of this bone substitute. The biopsy histology demonstrated the overall presence of newly formed vital bone and the resorption of the bone substitute. Its use for grafting the alveolar cleft is currently researched and it may become the new standard. As co-morbidity and prolonged operation time at the donor operation site are inherent to the alveolar cleft repair procedure, the use of the described bone substitute is winning progress.
European Journal of Oral Sciences, 2007
The purpose of mastication is to prepare food into a bolus that can be swallowed and easily diges... more The purpose of mastication is to prepare food into a bolus that can be swallowed and easily digested in the gut. During chewing, the food particles are reduced in size. The water in the saliva moistens the food particles, allowing the salivary amylase to access available starch (1). The salivary mucins bind masticated food into a coherent and slippery bolus that can easily be swallowed (2). The urge to swallow can be triggered by a threshold level in both food particle size and lubrication of the food bolus (3-5). Thus, both masticatory performance and salivary flow rate play an important role in preparing the food into a swallowable bolus.
European Journal of Oral Sciences, 2002
European Journal of Oral Sciences, 2011
Clinical Oral Implants Research, 2003
It could be hypothesised that attachments, which provide more retention against vertical and hori... more It could be hypothesised that attachments, which provide more retention against vertical and horizontal dislodgement, will be associated with more favourable parameters of oral function. This in vivo study is designed to provide data regarding initial retention force, loss of retention force after 3 months of function and postinsertion maintenance and complications associated with the use of magnet, bar-clip and ball attachments in mandibular overdenture treatment. Eighteen edentulous subjects received two permucosal implants in the inter-foramina region of the mandible, a new denture and three successive suprastructure modalities (magnet-, bar-clip and ball attachments). The retention force of the attachments at baseline and after 3 months was measured in a standardised way. The amount and type of postinsertion maintenance that was related to the attachment were evaluated. No differences in retention force at baseline and after 3 months of loading were observed for all three attachment types. The mean retention forces of magnet attachments, bar-clip attachments and ball attachments were 8.1, 31.3 and 29.7 N respectively. Functional maintenance complications related to the attachments were predominantly observed in 11/36 magnet attachments. Functional problems in the ball attachment group were relatively rare, easily manageable and seen in 4/36 attachments. The bar-clip attachments exhibited no maintenance problems at all.
Archives of Oral Biology, 2010
a r c h i v e s o f o r a l b i o l o g y 5 5 ( 2 0 1 0 ) 1 6 4 -1 6 9 Anxiolytic Antihypertensiv... more a r c h i v e s o f o r a l b i o l o g y 5 5 ( 2 0 1 0 ) 1 6 4 -1 6 9 Anxiolytic Antihypertensive Taste a b s t r a c t Objective: Assess the influence of salivary flow on physiological parameters of the stomatognathic system in patients who take beta-blockers or anxiolytic medications. Design: Sixty patients were divided into three groups based on the following criteria: Group 1, control (n = 20; no use of medication); Group 2, use of antihypertensive beta-blockers (n = 20); and Group 3, use of benzodiazepine anxiolytics (n = 20). Salivary flow was assessed by determining stimulated and non-stimulated flow/minute. The quantification of the sense of taste was determined on a visual analogue scale (VAS) using solutions of 0.9% NaCl (salty), 50% sucrose (sweet), 20% unsweetened coffee (bitter) and 4.2% vinegar (sour). The DMFT index (number of decayed/missing/filled teeth) was determined by a calibrated examination, following the criteria of the World Health Organization (WHO). Masticatory performance was assessed with an Optosil comminution test and Rosim-Ramler equation.
Journal of Oral Rehabilitation, 2009
Masticatory function can be impaired in temporomandibular disorders (TMDs) patients. We investiga... more Masticatory function can be impaired in temporomandibular disorders (TMDs) patients. We investigated whether treatment of subacute nonspecific TMD patients may influence oral function and clinical outcome measures. Fifteen patients with subacute TMD participated in the study. We quantified masticatory performance, maximum voluntary bite force, muscle activity and chewing cycle duration before and after treatment. Masticatory performance and bite force of patients were compared with the results obtained for an age-and gender-matched group of subjects without TMD complaints. Furthermore, we determined possible changes in anamnestic and clinical scores from questionnaires (mandibular function impairment questionnaire; MFIQ), pain scores and clinical outcome measures. Maximum bite force significantly increased, although the values after treatment were still significantly lower than those of the subjects without TMD complaints. The corresponding electromyography values did not show significant change after treatment. The masticatory performance of the patients remained unaltered; patients chewed significantly less efficient than controls. The average duration of chewing cycles significantly decreased after treatment. We observed a significant improvement in MFIQ scores. During the clenching and chewing tasks, the visual analogue scale scores were significantly higher than before these tasks. We may conclude that subacute temporomandibular joint disorders negatively influence chewing behaviour. Bite force, chewing cycle duration and also perceived mandibular function significantly improved after treatment, although the masticatory performance remained unaltered.
Archives of Oral Biology, 2007
Journal of Cranio-Maxillofacial Surgery, 2015
Segmental resection of the mandible causes functional, aesthetic and social problems affecting he... more Segmental resection of the mandible causes functional, aesthetic and social problems affecting health-related quality of life (HRQoL). It is often assumed that reconstruction with composite free flaps guarantees better function and aesthetics than bridging the defect with reconstruction plates. Using the European Organization for Research and Treatment of Cancer questionnaires (EORTC QLQ-C30 version 3.0 and EORTC QLQ-H&N35), we compared HRQoL in patients who received free fibula flaps versus reconstruction plates after segmental resection of the lateral mandible. Thirty-seven completed questionnaires (18 fibula reconstructions and 19 patients with reconstruction plates) were available. Reconstruction with a free fibula flap did not provide clear additional benefit to bridging the defect with a reconstruction plate after segmental resection of the lateral mandible. In particular aspects known to have the most impact on HRQoL like swallowing, speech and chewing were not influenced by the type of reconstruction. Reconstruction of segmental defects of the lateral mandible with free fibula flap and reconstruction plate resulted in comparable HRQoL. If dental rehabilitation by means of dental implants is not anticipated in the fibula, then plate reconstruction with adequate soft tissue remains a suitable technique for the reconstruction of segmental defects of the lateral mandible.
Journal of child neurology, Jan 19, 2015
Duchenne muscular dystrophy patients report masticatory problems. The aim was to determine the ef... more Duchenne muscular dystrophy patients report masticatory problems. The aim was to determine the efficacy of mastication training in Duchenne muscular dystrophy using chewing gum for 4 weeks. In all, 17 patients and 17 healthy age-matched males participated. The masticatory performance was assessed using a mixing ability test and measuring anterior bite force before, shortly after and 1 month after the training. In the patient group the masticatory performance improved and remained after 1-month follow-up, no significant changes in anterior maximum bite force was observed after mastication training. In the healthy subject the bite force increased and remained at the 1-month follow-up; no significant differences in masticatory performance were observed. Mastication training by using sugar-free chewing gum in Duchenne muscular dystrophy patients improved their masticatory performance. Since bite force did not improve, the working mechanism of the improvement in chewing may relate to cha...
International journal of oral and maxillofacial surgery, 2007
A simple, modified method to evaluate changes in the nasolabial soft tissues after orthognathic s... more A simple, modified method to evaluate changes in the nasolabial soft tissues after orthognathic surgery is presented. Eighteen healthy volunteers were photographed in a standardized manner with a 2-month interval. Pictures were taken with the soft tissues in repose and 'maximum closed mouth smile'. Discrepancies for repose and dynamic excursions (x and y coordinates) were calculated for the landmarks alare, crista philtri and cheilion. Multiple analysis of variance revealed no significant interaction for intra-observer variance and time of recording. Coefficients of reliability (repose: 90-99%, dynamic excursion (cheilion): >95%), Spearman correlation coefficients (repose: >0.8, dynamic: >0.6) and squared correlation (repose: >75%, dynamic: >50%) showed this method to be reliable for repose and dynamic excursions. The error of measurement was less than 1.8 mm for both repose and dynamic excursions (SD(differences)=0.9 mm). This is smaller than mean differences...
Nederlands tijdschrift voor tandheelkunde, 2006
The purpose of this study was to determine patient satisfaction with implant supported mandibular... more The purpose of this study was to determine patient satisfaction with implant supported mandibular overdentures using magnet, bar-clip and ball-socket attachments, and to assess the relation between maximum bite force and patient satisfaction. In a crossover clinical trial, 18 edentulous patients with lower denture complaints received 2 mandibular implants and new lower and upper dentures. The lower denture initially came without any kind of attachment system, but was fitted with one of the attachment types after 3 months. The attachments were changed 3 months thereafter, in random order. A questionnaire concerning denture complaints was given at baseline (with the old denture), after 3 months of functioning with the new denture without attachments and after 3 months of functioning with each of the attachments (within-subject comparison). In addition, at the end of the experiment patients were asked to express their overall satisfaction with their dentures on a visual analogue scale ...
Physiology and Behavior, 2003
Physiology & Behavior, 2006
The production of sufficient saliva is indispensable for good chewing. Recent research has demons... more The production of sufficient saliva is indispensable for good chewing. Recent research has demonstrated that salivary flow rate has little influence on the swallowing threshold. We examined the hypothesis that adding fluid to a food will influence the chewing process. Twenty healthy subjects chewed on melba toast, breakfast cake, carrot, peanut and Gouda cheese. In addition they chewed on these foods after we added different volumes of tap water or a solution of alpha-amylase. We measured jaw muscle activity and the number of cycles until swallowing. Furthermore, we obtained visual analogue scale (VAS) scores for texture and sound attributes for all foods and fluid conditions. The additional fluids significantly lowered muscle activity and swallowing threshold for melba, cake and peanut. The effect of alpha-amylase in the solutions was rather limited. Doubling the volume of tap water had a larger effect. Several texture and sound attributes of melba, cake and peanut were also significantly affected by the additional fluids. For melba, cake, and peanut we observed significant correlations between the physiology parameters and several attributes for the various fluid conditions. This indicates that the added fluid affects both the physiology (muscle activity and number of cycles) and the sensory perception of a number of texture and sound attributes. Adding fluid facilitates the chewing of dry foods (melba, cake), but does not influence the chewing of fatty (cheese) and wet products (carrot).
Physiology & Behavior, 2005
Practically all foods contain particles. It has been suggested that the presence of particles in ... more Practically all foods contain particles. It has been suggested that the presence of particles in food may affect the perception of sensory attributes. In the present study we investigated the effect of size and type (hardness and shape) of particles added to a CMC based vanilla custard dessert. The two types of particles included in the study were silica dioxide and polystyrene spheres, varying in size from 2 -230 µm. Eighteen trained adults participated in the study. They rated the sensation of 18 sensory flavor and texture attributes on a 100 point VAS-scale.
Physiology & Behavior, 2003
The effect of adding saliva or a saliva-related fluid (α-amylase solution and water) to custard p... more The effect of adding saliva or a saliva-related fluid (α-amylase solution and water) to custard prior to ingestion on the sensory ratings of odour, flavour, lip-tooth-feel, mouth-feel and afterfeel sensations was investigated. Saliva had previously been collected from the subjects and each subject received his/her own saliva. Sixteen subjects from a trained panel assessed 17 flavour and texture attributes of soy-and milk-based custard desserts. Immediately prior to administration, two different volumes (0.25 and 0.5 ml) of three different saliva-related fluids (saliva, α-amylase solution and water) were added to the product. The added volumes represented an approximately 33 % and 66 % increase of the volume of saliva present in the mouth during ingestion. The results show that addition of a fluid affected the mouth-feel attributes of melting, thickness and creamy. Melting was the only attribute on which the type of fluid had an effect, where saliva elicited a stronger melting effect than the α-amylase solution and water. The volume of the added fluid affected a number of attributes (thick and creamy mouth-feel and fatty after-feel). It can be concluded that in general the sensory attributes of semi-solids were relatively stable. Mouth and after-feel sensations were partly affected, while odour, flavour, and lip-tooth-feel sensations were not affected by an increase in volume of saliva or other saliva-related fluid during ingestion.
Oral Oncology, 2008
The objective of this study was to determine the value of dynamic contrast-enhanced MRI (DCE-MRI)... more The objective of this study was to determine the value of dynamic contrast-enhanced MRI (DCE-MRI) for the preoperative assessment of mandibular invasion in squamous cell carcinomas (SCC), adjacent or fixed to the mandible. DCE-MRI was performed with gadolinium diethylene triamine pentaacetic acid (Gd-DTPA). Data were obtained from 25 patients. From pharmacokinetic analysis of the tissue uptake of Gd-DTPA, the DCE-MRI parameters (k(ep), K(trans) and v(e)) were determined, with k(ep) representing the exchange rate constant, K(trans) the volume transfer constant and v(e) the volume of extracellular space per unit volume of tissue. The histology of the resection specimens was used as gold standard for the extent of mandibular invasion. SCC with medullary invasion showed higher mean k(ep) and K(trans) compared with SCC without medullary invasion (ANOVA, p<0.001). ROC analysis of k(ep) and K(trans) revealed reliable threshold values for medullary invasion. In conclusion, DCE-MRI can discriminate SCC with medullary invasion from SCC without medullary invasion and may serve as a valuable tool in preoperative tumour staging with regard to the delineation of medullary invasion.
Journal of Texture Studies, 2008
In the oral cavity, the food is subjected to several mechanical and chemical processes. It is fra... more In the oral cavity, the food is subjected to several mechanical and chemical processes. It is fractured by the teeth, diluted and broken down by saliva, heated or cooled by the ambient temperature of the mouth, formed into a bolus and finally swallowed. Numerous receptors in the oral cavity and nose respond to the initially ingested food and monitor the changes during processing. This leads to central perceptions of taste, odor, irritation and texture of the food. Most sensations associated with food texture occur only when the food is manipulated, deformed or moved across the oral receptors. In addition, people assessing the same stimulus differ in their ratings of that stimulus and their oral physiological parameters also exhibit inter-individual variations.
Journal of Texture Studies, 1986
ABSTRACT The masticatory performance of an individual has been quantified by determining the part... more ABSTRACT The masticatory performance of an individual has been quantified by determining the particle sizes of the comminuted food. Optosil, a silicon rubber, has been used as an artificial test food in clinical studies, because it has reproducible textural properties. A comparison between Optosil and several natural foods was made by measuring textural properties of Optosil, turnip, carrot, Gouda cheese and peanut. Several types of probes were used to imitate the cusp form of the teeth. Force-deformation plots revealed similar maximum firmness for Optosil, turnip and carrot, whereas peanut showed a larger firmness. The force needed to crush Optosil is much larger than for the natural foods, but it is well within the physiological range of healthy subjects. The reproducibility of the textural properties is better for Optosil than for the natural foods. The particle size distribution of Optosil broken by a testing machine was compared with the results obtained during chewing.
The Journal of Prosthetic Dentistry, 2011
The aim of this study was to evaluate patient satisfaction and clinical and prosthetic outcomes o... more The aim of this study was to evaluate patient satisfaction and clinical and prosthetic outcomes of two-implant mandibular overdenture treatment with different attachment types after 10 years of function. In a crossover clinical trial, 18 edentulous subjects with complaints regarding their mandibular dentures received two implants and a new denture with magnet, ball-socket, or bar-clip attachments that were applied in a random order. At the end of the experiment, the attachment type of their choosing was fitted in the overdenture. After 10 years, 7 subjects with a ball-socket and 7 subjects with a bar-clip attachment were available for evaluation. The same questionnaire from 10 years before was completed, and subjects were asked to express their overall appreciation of their dentures on a visual analog scale (VAS). Six scales of denture complaints were constructed. Mean scale and VAS scores between initial evaluation and after 10 years were compared. In addition, marginal probing depths, Bleeding Index, and radiographic marginal bone loss were assessed. There was no marked difference in satisfaction between subjects with ball-socket- and bar-clip-retained two-implant mandibular overdentures at initial evaluation and after 10 years of function. Patients' appreciation of their implant-retained denture was and remained high over time. Clinical parameters revealed healthy mucosal conditions and stable marginal bone levels, determined radiographically. Probing depths around implants provided with ball-socket attachments were slightly shallower than those with bar-clip attachments after 10 years of function (P < .05).
Journal of Cranio-Maxillofacial Surgery, 2013
The purpose of this study was to evaluate the use of synthetic bone graft material as a filling m... more The purpose of this study was to evaluate the use of synthetic bone graft material as a filling material at the mandibular symphysis donor site of autologous bone in children. A blinded patient group comprised 20 patients with unilateral (UCLP) or bilateral (BCLP) cleft of lip and palate, all with an indication for alveolar cleft repair. The study took the form of a prospective randomized clinical trial. We used lateral cephalograms for the measurement of the symphyseal donor area defect both peroperatively and at 12 months postoperatively. The data obtained were digitalized and the treatment outcome expressed in numbers. Comparisons with a previous study were made. Histology of biopsies and CT scans were used for visualising bone formation. This study demonstrates that the micro-structured, resorbable calcium phosphate ceramic provides good regeneration properties for the repair of a critical size bony defect in children. One year postoperatively, the measurements taken from lateral cephalograms show that there is scarcely any visible residual defect. Histological investigations of the bone biopsies show solid, induced bone formation and almost complete resorption of the micro-structured calcium phosphate. The findings of this study (novel in children) indicate that micro-structured resorbable calcium phosphate is an excellent alternative to autologous bone. The digital findings showed a restored donor site defect significantly indicating the efficacy (i.e., osteoconductivity and resorbability) of this bone substitute. The biopsy histology demonstrated the overall presence of newly formed vital bone and the resorption of the bone substitute. Its use for grafting the alveolar cleft is currently researched and it may become the new standard. As co-morbidity and prolonged operation time at the donor operation site are inherent to the alveolar cleft repair procedure, the use of the described bone substitute is winning progress.
European Journal of Oral Sciences, 2007
The purpose of mastication is to prepare food into a bolus that can be swallowed and easily diges... more The purpose of mastication is to prepare food into a bolus that can be swallowed and easily digested in the gut. During chewing, the food particles are reduced in size. The water in the saliva moistens the food particles, allowing the salivary amylase to access available starch (1). The salivary mucins bind masticated food into a coherent and slippery bolus that can easily be swallowed (2). The urge to swallow can be triggered by a threshold level in both food particle size and lubrication of the food bolus (3-5). Thus, both masticatory performance and salivary flow rate play an important role in preparing the food into a swallowable bolus.
European Journal of Oral Sciences, 2002
European Journal of Oral Sciences, 2011
Clinical Oral Implants Research, 2003
It could be hypothesised that attachments, which provide more retention against vertical and hori... more It could be hypothesised that attachments, which provide more retention against vertical and horizontal dislodgement, will be associated with more favourable parameters of oral function. This in vivo study is designed to provide data regarding initial retention force, loss of retention force after 3 months of function and postinsertion maintenance and complications associated with the use of magnet, bar-clip and ball attachments in mandibular overdenture treatment. Eighteen edentulous subjects received two permucosal implants in the inter-foramina region of the mandible, a new denture and three successive suprastructure modalities (magnet-, bar-clip and ball attachments). The retention force of the attachments at baseline and after 3 months was measured in a standardised way. The amount and type of postinsertion maintenance that was related to the attachment were evaluated. No differences in retention force at baseline and after 3 months of loading were observed for all three attachment types. The mean retention forces of magnet attachments, bar-clip attachments and ball attachments were 8.1, 31.3 and 29.7 N respectively. Functional maintenance complications related to the attachments were predominantly observed in 11/36 magnet attachments. Functional problems in the ball attachment group were relatively rare, easily manageable and seen in 4/36 attachments. The bar-clip attachments exhibited no maintenance problems at all.
Archives of Oral Biology, 2010
a r c h i v e s o f o r a l b i o l o g y 5 5 ( 2 0 1 0 ) 1 6 4 -1 6 9 Anxiolytic Antihypertensiv... more a r c h i v e s o f o r a l b i o l o g y 5 5 ( 2 0 1 0 ) 1 6 4 -1 6 9 Anxiolytic Antihypertensive Taste a b s t r a c t Objective: Assess the influence of salivary flow on physiological parameters of the stomatognathic system in patients who take beta-blockers or anxiolytic medications. Design: Sixty patients were divided into three groups based on the following criteria: Group 1, control (n = 20; no use of medication); Group 2, use of antihypertensive beta-blockers (n = 20); and Group 3, use of benzodiazepine anxiolytics (n = 20). Salivary flow was assessed by determining stimulated and non-stimulated flow/minute. The quantification of the sense of taste was determined on a visual analogue scale (VAS) using solutions of 0.9% NaCl (salty), 50% sucrose (sweet), 20% unsweetened coffee (bitter) and 4.2% vinegar (sour). The DMFT index (number of decayed/missing/filled teeth) was determined by a calibrated examination, following the criteria of the World Health Organization (WHO). Masticatory performance was assessed with an Optosil comminution test and Rosim-Ramler equation.
Journal of Oral Rehabilitation, 2009
Masticatory function can be impaired in temporomandibular disorders (TMDs) patients. We investiga... more Masticatory function can be impaired in temporomandibular disorders (TMDs) patients. We investigated whether treatment of subacute nonspecific TMD patients may influence oral function and clinical outcome measures. Fifteen patients with subacute TMD participated in the study. We quantified masticatory performance, maximum voluntary bite force, muscle activity and chewing cycle duration before and after treatment. Masticatory performance and bite force of patients were compared with the results obtained for an age-and gender-matched group of subjects without TMD complaints. Furthermore, we determined possible changes in anamnestic and clinical scores from questionnaires (mandibular function impairment questionnaire; MFIQ), pain scores and clinical outcome measures. Maximum bite force significantly increased, although the values after treatment were still significantly lower than those of the subjects without TMD complaints. The corresponding electromyography values did not show significant change after treatment. The masticatory performance of the patients remained unaltered; patients chewed significantly less efficient than controls. The average duration of chewing cycles significantly decreased after treatment. We observed a significant improvement in MFIQ scores. During the clenching and chewing tasks, the visual analogue scale scores were significantly higher than before these tasks. We may conclude that subacute temporomandibular joint disorders negatively influence chewing behaviour. Bite force, chewing cycle duration and also perceived mandibular function significantly improved after treatment, although the masticatory performance remained unaltered.