Biomedical subjects

M A van 't Hof

Publications and source records attributed to M A van 't Hof.

At least 19 recordsLinked to original sources

PubMed2006

Caries-preventive effect of resin-based and glass ionomer sealants over time: a systematic review.

INTRODUCTION: The difference in preventing dentine lesion development between resin-based and glass ionomer sealant materials is unclear. Two recently published reviews were unable to conclude on the difference because the comparison was an exclusion criterion in one review and there were statistical shortcomings in the relevant papers in the other (Cochrane) review. OBJECTIVES: The aim of the present investigation was to carry out a systematic review on the caries-preventive effect of these two types of sealant materials under more liberal exclusion criteria concerning the statistical presentations in the publications. METHODS: Based on five exclusion criteria, the literature search in the electronic libraries PubMed and MEDLINE and the publications retrieved in the Cochrane review, revealed 12 eligible publications for analyses. A variety of glass ionomers and resin-based sealant materials had been applied in the included studies. Attributable risk (AR) was chosen rather than relative risk (RR), as used in the Cochrane review, because RR is very instable in a low caries population. RESULTS: There was no consistent pattern observed with respect to the caries-preventive effect of either resin-based or glass ionomer sealants. Therefore, it was impossible to calculate an overall AR. CONCLUSIONS: There is no evidence that either resin-based or glass ionomer sealant material is superior to the other in preventing dentine lesion development in pits and fissures over time.

Dental Caries↗

PubMed2006

Risk factors of early childhood caries in a Southeast Asian population.

A retrospective cohort study on ECC and associated factors was conducted among mothers with 25- to 30-month-old infants in a community where prolonged breastfeeding was common practice. All infants who consumed sugary supplementary food or rice that was pre-chewed by the mother, or who fell asleep with the breast nipple in their mouths, had ECC. Infants without those habits, and who were breastfed up to 12 months, had no ECC. Breastfeeding during the day beyond the age of 12 months was not associated with ECC, but infants who were breastfed at night > 2 times had an OR for ECC of 35 (CI 6-186), and those who were exposed to > 15 min per nocturnal feeding had an OR for ECC of 100 (CI 10-995). The present study indicates that, in this population, besides the consumption of sugars and pre-chewed rice, nocturnal breastfeeding after the age of 12 months poses a risk of developing ECC.

Breast Feeding↗

PubMed2006

Caries-inhibiting effect of chlorhexidine varnish in pits and fissures.

Evidence regarding the caries-inhibiting effect of chlorhexidine varnish is inconclusive. This study investigated the caries-inhibiting effect of the varnish EC40 on pits and fissures of first permanent molars. A two-year randomized controlled trial was carried out among 461 six- to seven-year-old children. In a split-mouth design, one group of molars received EC40 at baseline, 6, 12, and 18 months, and another group at baseline, 3, 12, and 15 months. Control molars did not receive EC40. Adherence to the treatment protocol was good. The dropout rate was 17%. Blinded examiners performed dental examinations. The caries-inhibiting effects of the two EC40 application schemes were comparable. The prevented fraction of caries was 25% (95%CI, 1%, 49%, p = 0.04) after 2 years and 9% (95%CI, -11%, 29%, p = 0.20) one year after termination of the trial, suggesting a short-term benefit from the use of EC40. The efficiency of EC40 is questionable in low-caries-incidence child populations.

Anti-Infective Agents, Local↗

PubMed2006

Survival of ART and amalgam restorations in permanent teeth of children after 6.3 years.

The null hypothesis tested was that there is no difference in the survival percentages of all restorations placed through the Atraumatic Restorative Treatment (ART) approach, with high-viscosity glass ionomer, and those produced through the traditional approach, with amalgam (TA), in the permanent dentitions of children after 6.3 years. Using a parallel group design, we randomly assigned a total of 370 children, aged 6 to 9 years, to the ART group and 311 children, also aged 6 to 9 years, to the TA group. Eight dentists placed a total of 1117 single- and multiple-surface restorations. The cumulative survival percentages for ART glass-ionomer restorations were statistically significantly higher than those of amalgam restorations at all time intervals except the first (p < or = 0.044). After 6.3 years, the cumulative survival percentages of ART and amalgam restorations were 66.1% (SE = 3.1%) and 57.0% (SE = 3.3%), respectively. We concluded that the restorations produced with the ART approach, with high-viscosity glass ionomer, survived longer than those produced with the traditional approach, with amalgam, in the permanent teeth of young children.

Actuarial Analysis↗

PubMed2006

Plaque removal by young children using old and new toothbrushes.

There is inconclusive evidence about the relationship between toothbrush wear and plaque removal. This randomized cross-over clinical trial aimed to validate or invalidate non-inferiority in the plaque-removal efficacy of old vs. new toothbrushes in the hands of 7- and 8-year-old children. The lower limit for non-inferiority was set a priori as a difference in plaque score<15%. Children (n=101) brushed, in the first session, with either their 14-month-old toothbrush or a new one, and in the second session vice versa. The mean Quigley-Hein plaque score, before and after children brushed with old brushes, was 2.9 and 2.4, and with new brushes 2.8 and 2.1. The plaque score after they brushed with the new toothbrush was 10.9% lower (p<0.001) than after they brushed with the old toothbrush. The confidence interval of 7.6%-13.9% was within the acceptance band (<15%), and non-inferiority of old toothbrushes in the hands of these children was validated.

Child↗

PubMed2005

A measuring system for facial aesthetics in Caucasian adolescents: reproducibility and validity.

A new measuring system to judge facial aesthetics in young Caucasians is presented. The system uses sets of three photographs (one frontal, one three-quarter smiling, and one lateral) as a stimulus. Scores are performed on a visual analogue scale (VAS) with separate sets of reference photographs for girls and boys. The choice of the reference photographs was based on a panel evaluation of facial aesthetics of 40 boys and 40 girls from the archive of the orthodontic department. Reproducibility of the new measuring system was tested on a series of photographic sets (one frontal, one three-quarter smiling, and one lateral view) of 64 patients, using a panel of 78 adult laymen and 89 professionals. The panel members assessed these sets of photographs on a VAS, in relation to the reference sets. The system was shown to be reproducible. Although the intra-observer reproducibility was low, the reliability coefficient was excellent (Cronbach's alpha > or = 0.98). Validity was tested by comparing the scores on the new scales with those of the three-quarter smiling photographic views on an earlier published scale. The correlation between the ratings on the new measuring system and the earlier published scale was 0.82 for laymen and 0.77 for professionals. The new system is simple and flexible in its use, and reproducible and valid for assessing facial aesthetics in young Caucasians. The system can be used in further investigations on the evaluation of facial aesthetics.

Adolescent↗

PubMed2005

Classification, reproducibility and prevalence of root proximity in periodontal patients.

AIM: The primary aim of this study is to define and classify root proximity. The secondary aim is to examine the reproducibility of the measurement tools, to study the prevalence per inter-dental area and to examine whether the distance from the cemento-enamel junction (CEJ) to the bone crest (BC) differs between sites with root proximity and their contra-lateral sites without root proximity. MATERIAL AND METHODS: In order to indicate the location of root proximity, a modification of the Shei ruler was developed, dividing the roots into three equal parts. A radiographic template was used to measure the distance between the roots, in this way determining the severity of the root proximity. The reproducibility of the measurement tool was tested, the prevalence was calculated and the distances CEJ-BC for root proximity sites and contra-lateral sites were recorded. RESULTS: A two-digit classification was obtained dividing the root into three locations [apical (A), between (B) and coronal (C)], with each location having the possibility of three different severities of root proximity. The described modification of the Shei ruler and the measurement tool for the severities can be considered as reproducible measurement tools. Root proximity was most prevalent in maxillary molars and between central and lateral incisors in the maxilla and mandible. There was no difference in CEJ-BC distance between the root proximity sites and their contra-lateral sites. CONCLUSION: We can conclude that a two-digit classification for root proximity was established. Root proximity in untreated periodontal patients has no influence on the distance CEJ-BC. However, the location of root proximity becomes important from the moment that periodontal disease has been established at that site. The severity of root proximity is important for choosing treatment options. There is a striking similarity between bone loss patterns and tooth loss and the location of inter-dental spaces where root proximity is most prevalent.

Adolescent↗

PubMed2005

Root proximity as a risk marker for periodontal disease: a case-control study.

AIM: The aim of this study is first, to examine the prevalence, symmetry and spread of root proximity using the measurement tools and classification as described in part I of the study, and second to examine whether root proximity is a risk marker for periodontal disease. MATERIAL AND METHODS: The radiographs of 227 patients were examined. The study consisted of a study group of 197 patients with advanced periodontal disease with at least one site with bone loss more than one third of the root length and 30 controls without periodontal disease. Every inter-proximal space was assessed on the full-mouth radiographs and a score was assigned according to severity and location. Consequently prevalence of severity and location, symmetry, spread and an odds ratio and relative risk for periodontal disease was calculated. RESULTS: Root proximity is a symmetrical and localized but widespread phenomenon in periodontal patients and to lesser extend in the non-periodontal control group. In periodontal patients root proximity was most often encountered in the coronal and intervening part whereas subjects without periodontal disease had more root proximity in the apical and intervening part where it is less critical. Subjects with bilateral root proximity had a 3.6 times higher chance to have periodontitis. CONCLUSION: Root proximity must be taken into consideration as a risk marker for periodontal disease.

Adolescent↗

PubMed2005

Professionally applied fluoride gel in low-caries 10.5-year-olds.

The question has been raised whether low-caries children regularly using fluoride toothpaste will benefit from the professional application of additional fluoride gel. To investigate the caries-reducing effect of semi-annually-applied neutral 1% sodium fluoride gel, we carried out a double-blind randomized controlled clinical trial (n = 594) in a child population, initially aged 9.5-11.5 years, with baseline caries experience of D3MFS = 0 (decayed, missing, and filled tooth surfaces of permanent teeth). The mean number of tooth surfaces saved from caries development by fluoride gel application after 4 years was 0.2 D3MFS (SE = 0.17). The preventive fraction (PF) showed a mean relative effect of professionally applied fluoride gel of 18%. The cariostatic effect of the fluoride gel on pits and fissures would have been influenced by the sealant strategy in the study. Professionally applied fluoride gel showed no statistically significant effect on mean D3MFS score in low-caries 9.5- to 11.5-year-olds.

Cariostatic Agents↗

PubMed2005

[Implant-retained overdentures compared with complete dentures with or without preprosthetic surgery. A prospective study followed over 10 years].

The aim of this prospective randomized clinical trial was to evaluate and compare a set of clinical items and satisfaction of a group of edentulous patients during a ten-year follow-up. They were treated according to one of the following modalities: 61 patients with a mandibular overdenture on two implants (IMP-group), 60 patients with conventional complete dentures (VP-group) and 28 patients with a complete denture after preprosthetic surgery (MVP-group). It can be concluded that enosseous implants, serving as retention for a mandibular overdenture, have a high survival rate after ten years of follow-up (93%). The mean satisfaction score of the VP-group was lower than that of the IMP-group. The mean satisfaction score of the MVP-group was lower than that of the IMP-group.

Dental Implantation, Endosseous↗

PubMed2004

Demand for orthodontic treatment among 9-18 year-olds seeking dental care in Dar-es-Salaam, Tanzania.

OBJECTIVE: To investigate the demand for orthodontic treatment among 9-18 olds seeking dental care in Dar-es-Salaam, Tanzania. DESIGN: Case-control, interview and clinical study. SETTINGS: Children seeking dental care. MAIN OUTCOME MEASURES: Demand for orthodontic treatment. RESULTS: Most of the children (85%) in the case group attended the dental clinic because of crowding. Aesthetic impairment (AC grades 8-10) and severe malocclusions (DHC grades 4-5) were higher in cases than in controls being 47 and 5%; and 67 and 18%, respectively (p<0.0001). Absolute need (combined AC grade 8-10 and DHC 4-5) was found in 29% of the cases and 5% of the controls (p<0.0001). A relative probability for a child with absolute need to seek orthodontic treatment was 7.9 higher (95%) CI for OR = (5,13), compared to a child without an absolute need for orthodontic treatment. The most prevalent severe occlusal feature placing cases in the highest need category was crowding (74%). For the cases, it was mainly a mother (45%) who first recognized the problem in the family, and tooth extraction (62%) was the most common expected mode of treatment. Most parents (96%) were prepared to pay for their children's orthodontic treatment. CONCLUSION: Most children in the case group had come to the clinic due to crowding. Ectopic canines were the driving factor for children and parents to seek orthodontic care. Further studies are recommended to map the demand for orthodontic treatment in the Tanzanian rural settings.

Adolescent↗

PubMed2004

Need for orthodontic treatment among Tanzanian children.

OBJECTIVE: To determine the need for orthodontic treatment among Tanzanian Bantu children. DESIGN: Prospective study using dental casts. SETTING: Sixteen randomly selected schools from the Ilala district, Dar-es-Salaam, Tanzania. SUBJECT: Six hundred and forty three Tanzanian children from an urban district. METHOD: Dental casts of 643 Tanzanian subjects in age groups 3-5, 6-8, 9-11 and 15-16 years, were assessed using the Index of Orthodontic Treatment Need (IOTN). MAIN OUTCOME MEASURES: Need for orthodontic treatment. RESULTS: Aesthetic treatment need (AC grades 8-10) and dental health component (DHC grades 4-5) occurred in 5-15% and 16-36% of the studied children, respectively. The need measured by DHC increased significantly between the two oldest age groups. An absolute need measured by combining AC grades 8-10 and DHC grades 4-5 was found in 3-12% of the subjects and it increased significantly with age (p<0.03). The most prevalent severe occlusal feature placing the children in the great need category was cross bite. While about 3-19% of the children had distal occlusion (Angle's Class II), mesial molar occlusion (Angle's Class III) was rare, occurring in 1-3% of the children. CONCLUSIONS: This study provides baseline data on the need for orthodontic treatment among Tanzanian children that may be useful for the public oral health service to determine priority for orthodontic treatment as part of comprehensive child oral health care in Tanzania.

Adolescent↗

PubMed2002

Osteoblast differentiation of bone marrow stromal cells cultured on silica gel and sol-gel-derived titania.

Primary cultures of osteogenic precursor cells derived from rat bone marrow stroma were performed on commercially available pure titanium discs (Ti c.p.) and surface modified Ti c.p.using a sol-gel technique (Ti sol). In separate repeated experimental runs, cell behavior and in vitro mineralization were compared with cultures on silica gel bioactive glass discs (S53P4). All substrates were incubated in simulated body fluid prior to the experiment. Overall, variable effects between experimental runs were seen. Apparently, this was due to the heterogeneous nature of the used cell population. Therefore, only careful conclusions can be made. Initial cell adhesion and growth rates between 3 and 5 days of culture--analyzed by cell numbers--were in general comparable for the two titanium substrates, while initial growth up to day 3 is suggested to be higher in Ti c.p. compared to Ti sol. Although initial cell adhesion on the S53P4 glass discs was lower than the titanium substrates, cell growth rates appeared to be higher on the silica gel compared to the two titanium substrates. Further, there were some indications that the early and late osteoblast differentiation markers, alkaline phosphatase and osteocalcin, monitored up to day 24, were elevated in Ti c.p cultures compared to Ti sol cultures. There were no differences observed in in vitro mineralization between the titanium groups. S53P4 seemed to display a substantially higher differentiating capacity for both osteogenic cell markers as well as in vitro mineralization compared to the two titanium substrates.

Alkaline Phosphatase↗

PubMed2002

The reproducibility of cephalometric measurements: a comparison of analogue and digital methods.

The aim of this study was to compare the reproducibility of longitudinal cephalometric measurements between analogue and digital methods using two different resolutions. Cephalometric radiographs of 20 patients were selected at the start (T1) and end (T2) of treatment: 24 cephalometric variables were calculated at T1 and T2, and their increments (T2 - T1) were also evaluated. All measurements were performed twice by two observers. Quality of methods [analogue, digital: 300 and 600 dots per inch (DPI) resolution] was evaluated by comparing the reliability coefficients and the total error between the digital and analogue methods. The inter-observer agreement was good. The 300 DPI was comparable to the analogue method. The reproducibility for the variables was comparable, but mandibular incisor increments tended to show better results with the 300 DPI method, whereas skeletal jaw relationship increments were not reliable with either method. Maxillary incisor increments, however, were reliable with both methods. The 300 and 600 DPI resolutions were found to be comparable. Scanning of cephalometric radiographs at a resolution of 300 DPI is sufficient for clinical purposes and comparable to analogue cephalometrics. However, all methods were found to be poor in assessing skeletal jaw relationships longitudinally.

Cephalometry↗

PubMed2002

[Implant-retained overdentures compared with complete dentures with or without preprosthetic surgery. Satisfaction and subjective chewing capabilities].

The aim of this prospective randomized clinical trial was to evaluate and compare a set of clinical items and satisfaction of a group of edentulous patients during a 5-year follow-up. They were treated according to one of the following modalities: 61 patients with a mandibular overdenture on two implants (IMP-group), 60 patients with a conventional complete denture (VP-group) and 28 patients with a complete denture after preprosthetic surgery (MVP-group). It can be concluded that endosseous implants, serving as retention for a mandibular overdenture, have a high survival rate after 5 years of follow-up (93%). The mean satisfaction score of the VP-group was lower than of the IMP-group. The mean satisfaction score of the MVP-group is lower than of the IMP-group.

Dental Implantation, Endosseous↗

PubMed2001

Pain and instability during biting with mandibular implant-retained overdentures.

We tested in a randomized controlled clinical trial the effect of pain and instability of dentures on bite force with different degrees of mucosal support. The trial involved 3 groups who had received: 1) a new conventional denture (CD-group), 2) an implant-mucosa-borne overdenture on 2 IMZ implants (IMZ-group) or 3) a mainly implant-borne overdenture retained by a transmandibular implant (TMI-group). Fifty-three women and 15 men, mean age 59 years, participated in this study. Bite force measurements were made unilaterally with a transducer and bilaterally with a bite fork. After the measurements, subjects were asked whether or not biting had caused pain or tilting of one of the dentures. Significantly more complete-denture wearers reported pain. They reported more frequent pain in the mandible than in the maxilla (P < 0.001), whereas implant-groups seemed to experience more often pain in the maxilla. On the transducer, maxillary dentures of the CD-group tilted less (P < 0.01) and mandibular dentures more (P < 0.05) compared to the implant-groups. With the bite fork, tilting occurred more often in the incisal-cuspid area than in the molar region (P < 0.001). No effect of pain and tilting was observed on maximum bite force. It appears that oral implants used to stabilize mandibular dentures permit subjects to exert higher bite forces and reduce the pain as otherwise felt in the mandible during maximum biting. Due to this stabilization, pain and instability of the maxillary denture can become the limiting factor for a further increase in bite force.

Adult↗

PubMed2001

Effect of a consensus statement on initial treatment for traumatic dental injuries.

The aim of this study was to investigate the influence of a consensus statement on dental practitioners' choice of initial treatment for traumatic dental injuries. Dental practitioners working at government dental clinics in eight cluster sample regions of mainland Tanzania were requested to participate in the study; that is, to record the treatment they provided to children aged 1-17 years seeking dental consultation after injury for a period of 12 months. Six months after the beginning of data collection, a consensus statement was introduced. After the dental practitioners received the consensus statement, the correct treatment they provided increased from 51% to 57%. The unnecessary treatments increased from 54% to 59%, while wrong treatments decreased from 55% to 42%. Only a small improvement was observed in the percentage of correct treatments, but there was a slightly significant improvement in the percentage of wrong treatments provided before and after introduction of the consensus statement. We conclude that the consensus statement had a slight influence on the dental practitioners' choice of initial treatment for dental trauma in the desired direction.

Adolescent↗

PubMed2001

Modified sharp method: factors influencing reproducibility and variability.

BACKGROUND AND OBJECTIVES: In rheumatoid arthritis, joint radiography is still the most frequently used instrument to assess the progression of joint damage. Unfortunately, the poor quality of the radiographic scoring methods available has a negative impact on the power in clinical trials. This study focuses on the influence of the following 4 factors on radiographic scores according to van der Heijde's modification of the Sharp method: intraobserver variation, interobserver variation, follow-up time, and number of measurement occasions within a patient series. METHODS: One hundred and seventy-two patients in the early stages of rheumatoid arthritis were followed up. During the first 3 years, radiographs of the hands and feet were taken twice yearly and scored by 3 observers. The scoring process was repeated after an additional 3-year period. Correlation coefficients and differences between observers were calculated to define variability. The influence of the 4 factors on variability was studied. RESULTS: One observer assigned a significantly higher score than the other 2, who had been trained together. Interobserver variability decreased as follow-up time increased. Interobserver correlation coefficients became higher, with smaller differences between observers for progression scores than for absolute scores. Increasing the number of measurements within a patient series led to higher scores. Intraobserver correlation coefficients were high, and a training effect occurred when the time between measurements was 1 year, resulting in lower scores. CONCLUSIONS: This study demonstrates that, and shows how, the investigated factors influence the variability of the modified Sharp method. It is extremely important to take interobserver variation into account when designing protocols for multicenter clinical trials. A progression scoring method is recommended for studies assessing radiographic damage or clinical trials.

Arthritis, Rheumatoid↗