Biomedical subjects

A M Kuijpers-Jagtman

Publications and source records attributed to A M Kuijpers-Jagtman.

At least 19 recordsLinked to original sources

PubMed2006

CMT-3 inhibits orthodontic tooth displacement in the rat.

OBJECTIVE: Orthodontic tooth movement requires extensive remodeling of the periodontal ligament (PDL) and the alveolar bone. Osteoclasts resorb bone, allowing teeth to migrate in the direction of the force. Matrix metalloproteinases (MMPs) are able to degrade the extracellular matrix of the periodontal tissues. Chemically modified tetracyclines (CMTs) can inhibit MMPs, but lack antimicrobial activity. We hypothesize that CMT-3 will decrease the rate of orthodontic tooth movement in the rat. DESIGN: Eighteen Wistar rats received a standardized orthodontic appliance at one side of the maxilla. During 14 days, three groups of six rats received a daily dose of 0, 6 or 30mg/kg CMT-3, and tooth displacement was measured. Thereafter, osteoclasts were counted on histological sections using an ED-1 staining. Multi- and mononuclear ED-1-positive cells in the PDL were also counted. In addition, sections were stained for MMP-9. RESULTS: CMT-3 significantly inhibited tooth movement (p=0.03) and also decreased the number of osteoclasts at the compression sides in the 30mg/kg group (p<0.05). Significantly more mono- than multinuclear ED-1-positive cells were present in the PDL, but no significant differences were found between the dosage groups. Osteoclasts in the 30mg/kg group seemed to contain less MMP-9 than in the control. CONCLUSIONS: CMT-3 inhibits tooth movement in the rat, probably by reducing the number of osteoclasts at the compression side. This might be due to induction of apoptosis in activated osteoclasts or reduced osteoclast migration. Reduced MMP activity by CMT-3 might also directly inhibit degradation of the organic bone matrix.

Alveolar Process↗

PubMed2006

Objective measures as indicators for facial esthetics in white adolescents.

The objective of this study was to examine the contribution of objective measures representing anterior-posterior and vertical characteristics, dental esthetics, or their combination that are used in daily orthodontic practice in the assessment of facial esthetics. A panel of 78 laymen evaluated facial esthetics of 32 boys and 32 girls, stratified over the four Angle classes, on a visual analogue scale. The relation between the objective parameters and facial esthetics was evaluated by backward multiple regression analysis. Dental esthetics as expressed by the Aesthetic Component of the Index of Orthodontic Treatment Need (AC/IOTN) appeared to be the most important indicator for facial esthetics. A new parameter, the "horizontal sum" was found to be a reliable variable for the anterior-posterior characteristics of the patient. Addition of this newly defined parameter to the AC/IOTN improved the prognostic value from 25% to 31%.

Adolescent↗

PubMed2006

Chemically modified tetracyclines stimulate matrix metalloproteinase-2 production by periodontal ligament cells.

BACKGROUND AND OBJECTIVE: The purpose of this study was to investigate the effects of chemically modified tetracyclines (CMTs) on the production of gelatinases [matrix metalloproteinase (MMP)-2 and -9] by human periodontal ligament (PDL) cells, and on the activity of recombinant gelatinases. MATERIAL AND METHODS: Human PDL cells were cultured with CMT-1, -3, -5, -7 or -8 in concentrations of 0, 1, 5, 10, 20, 50, 100, 200 and 500 microm. Gelatin zymography was used to determine MMP-2 and -9 production of the cells. The amount of DNA present in the cultures was analyzed using a fluorescent assay. The cytotoxicity of the CMTs was also determined. Recombinant human MMP-2 and -9 were incubated with the CMTs (0-500 microm) and their activity was analyzed using an internally quenched fluorogenic substrate. RESULTS: MMP-2 production was stimulated up to sevenfold by CMT-1, -3, -7 and -8 at low concentrations (10-200 microm). No significant amounts of MMP-9 were produced. In contrast, MMP-2 and -9 activity was reduced by approximately 10-40-fold at higher concentrations (200-500 microm). CMT-5 had no effect on the production or on the activity of MMP-2 and -9. Only CMT-3 and -8 had cytotoxic effects on the PDL cells at the highest concentrations. CONCLUSION: Surprisingly, CMTs are able to stimulate MMP-2 production at relatively low concentrations. However, at higher concentrations they exert a much stronger inhibitory effect on gelatinase activity. A possible stimulatory effect of CMTs on MMP production should be considered in their clinical use.

Analysis of Variance↗

PubMed2006

Fluid shear stress inhibits TNFalpha-induced osteocyte apoptosis.

Bone tissue can adapt to orthodontic load. Mechanosensing in bone is primarily a task for the osteocytes, which translate the canalicular flow resulting from bone loading into osteoclast and osteoblast recruiting signals. Apoptotic osteocytes attract osteoclasts, and inhibition of osteocyte apoptosis can therefore affect bone remodeling. Since TNF-alpha is a pro-inflammatory cytokine with apoptotic potency, and elevated levels are found in the gingival sulcus during orthodontic tooth movement, we investigated if mechanical loading by pulsating fluid flow affects TNF-alpha-induced apoptosis in chicken osteocytes, osteoblasts, and periosteal fibroblasts. During fluid stasis, TNF-alpha increased apoptosis by more than two-fold in both osteocytes and osteoblasts, but not in periosteal fibroblasts. One-hour pulsating fluid flow (0.70 +/- 0.30 Pa, 5 Hz) inhibited (-25%) TNF-alpha-induced apoptosis in osteocytes, but not in osteoblasts or periosteal fibroblasts, suggesting a key regulatory role for osteocyte apoptosis in bone remodeling after the application of an orthodontic load.

Adaptation, Physiological↗

PubMed2006

[Kabuki syndrome, a congenital syndrome with multiple anomalies].

The characteristics of a 5-years old girl, referred to a multidisciplinary team for cleft lip and palate because of speaking problems, were diagnosed as Kabuki syndrome. The Kabuki syndrome is a congenital syndrome of unknown aetiology, diagnosed based on a combination of clinical findings. It is characterised by distinctive facial features, skeletal anomalies, dermatoglyphic abnormalities, developmental delay and mild to moderate mental retardation. Children with the syndrome often have oral manifestations such as cleft palate, missing permanent teeth and conic crowns of upper incisors. The Kabuki syndrome was first described regarding the Japanese population but it is now known to occur in many other races as well. In a recent publication, 20 Dutch patients with Kabuki syndrome were described.

Abnormalities, Multiple↗

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

Regulatory effects of FGF-2 on the growth of mandibular condyles and femoral heads from newborn rats.

The secondary cartilage of the mandibular condyle is considered to be adaptive to functional factors. In the last decades, growth factors have also been shown to be potent regulators of cartilage metabolism. Moreover, it has been suggested that growth factors may differentially regulate the growth of primary and secondary cartilages. However, only a few studies have made a direct comparison of the effects of growth factors on both cartilages. Therefore, the aim here was to compare the effects of FGF-2 on secondary cartilage of the mandibular condyle and primary cartilage of the femoral head from 4-day-old rats in vitro. Cartilages were cultured for 1, 7 and 14 days with 0 and 100 ng/mL FGF-2. We evaluated the effects of FGF-2 on growth, tissue organisation, DNA and glycosaminoglycan (GAG) synthesis and GAG and collagen content. With FGF-2, the morphology of the mandibular condyles changed and the GAG and collagen contents were reduced. However, the growth of the mandibular condyles was not affected. On the contrary, the growth of the femoral heads was strongly reduced due to an inhibition of chondrocyte hypertrophy. In both cartilages, FGF-2 stimulated DNA synthesis in short-term cultures and reduced it in long-term cultures. In conclusion, FGF-2 had a larger effect on the metabolism of the mandibular condyles as compared to the femoral heads. However, the growth of the femoral heads was strongly reduced while that of the mandibular condyles was not affected.

Animals↗

PubMed2005

Teunissen-Cremers syndrome: a clinical, surgical, and genetic report.

OBJECTIVE: To describe clinical and radiologic features, results of ear surgery, and genetic analysis in three families with Teunissen-Cremers syndrome. DESIGN: Case series. SETTING: Tertiary referral center. BACKGROUND: The NOG gene encodes the protein noggin, which has antagonist action in osteogenesis. Malformation of bones and joints may result from defects in noggin. Teunissen-Cremers syndrome is caused by mutations in the NOG gene. Two mutations in this gene were reported previously. The proximal symphalangism-hearing impairment syndrome, also caused by mutations in the NOG gene, is characterized by proximal symphalangism, conductive hearing loss, and occasionally synostoses. METHODS: We examined nine affected members of three Dutch families. Reconstructive middle ear surgery was performed in five patients (nine ears), and we sequenced the NOG gene in these families. RESULTS: Affected members had conductive hearing impairment, hyperopia, and broad thumbs and first toes with brachytelephalangia. Surgery manifested stapes ankylosis with additional incudal fixation frequently in the fossa incudis. Air-bone gaps decreased to less than 10 dB in six ears. Genetic analysis revealed three new mutations in the NOG gene. CONCLUSION: The Teunissen-Cremers syndrome is an entity in its clinical presentation, distinct from other syndromes with proximal symphalangism and hearing impairment. So far, in five families with Teunissen-Cremers syndrome, four truncating mutations and one amino acid substitution were found in the NOG gene. The majority of other mutations found in this gene are missense mutations, which might result in some residual protein activity. Reconstructive middle ear surgery is an option for treatment.

Abnormalities, Multiple↗

PubMed2005

Myofibroblasts in palatal wound healing: prospects for the reduction of wound contraction after cleft palate repair.

The surgical closure of orofacial clefts is considered to impair maxillary growth and dento-alveolar development. Wound contraction and subsequent scar tissue formation, during healing of these surgical wounds, contribute largely to these growth disturbances. The potential to minimize wound contraction and subsequent scarring by clinical interventions depends on the surgeon's knowledge of the events responsible for these phenomena. Fibroblasts initiate wound contraction, but proto-myofibroblasts and mature myofibroblasts are by far the most important cells in this process. Myofibroblasts are characterized by their cytoskeleton, which contains alpha-smooth-muscle actin. Additionally, their contractile apparatus contains bundles of actin microfilaments and associated contractile proteins, such as non-muscle myosin. This contractile apparatus is thought to be the major force-generating element involved in wound contraction. After closure of the wound, the myofibroblasts disappear by apoptosis, and a less cellular scar is formed. A reduction of contraction and scarring might be obtained by inhibition of myofibroblast differentiation, stimulation of their de-differentiation, stimulation of myofibroblast apoptosis, or impairment of myofibroblast function. In this review, we will discuss all of these possibilities, which ultimately may lead to a better outcome of cleft palate surgery.

Animals↗

PubMed2004

Growth stimulation of mandibular condyles and femoral heads of newborn rats by IGF-I.

Primary and secondary cartilage differ in embryonic origin and are generally considered to have a different mode of growth. However, few experimental studies exist that directly compare the two types of cartilage and their growth regulation. The regulation of cartilage growth is a complex mechanism involving growth factors like insulin-like growth factor-I (IGF-I). The purpose of this study was to compare the growth of mandibular condyles of 4-day-old rats with that of femoral heads in vitro and to analyze the effects of IGF-I. Explants were cultured for up to 2 weeks with 0, 5, and 25 ng/ml IGF-1. Both, 5 and 25 ng/ml IGF-I significantly stimulated growth of the mandibular condyles while only 25 ng/ml IGF-I stimulated growth of the femoral heads. IGF-I increased glycosaminoglycan synthesis of both condylar and femoral cartilage. However, only the DNA synthesis of the mandibular condyles was significantly increased by IGF-I while that of the femoral heads was not affected. It is concluded that IGF-I stimulates growth of both secondary condylar cartilage and primary femoral cartilage. The mandibular condyle appears to be more sensitive to IGF-I than the femoral head, which may partly be due to the different developmental stage.

Animals↗

PubMed2004

Comparison between the opinions of Tanzanian parents and their children on dental attractiveness.

The objective was to investigate the opinion of Tanzanian parents on dental attractiveness and to compare their opinion with that of their children. A prestructured questionnaire with 18 intraoral frontal photographs was given to 286 parents and their children aged 9-18 years. The photographs represented various types of occlusion traits, with the first 10 intraoral photographs representing grade 1-10 of the aesthetic component (AC) of the index of orthodontic treatment need, and the remaining eight photographs were added to represent malocclusions that are often seen in Tanzania. Basic statistical techniques were used to analyze the data. Photographs showing severe deviations were perceived by both children and parents as the most unattractive. The opinion was significantly correlated with children's age (P = .02) and sex (P < .0005), with older girls tending to dislike photographs showing severe deviations the most. The mean of the opinion for the photographs showing some spacing with overbite < or = 2 mm or open bite and overbite > 2 mm fell in the middle of the scale, with a tendency toward unattractiveness. Photographs matching 8-10 on the AC scale were perceived as the most unattractive, indicating what could be a lay person's priority when considering an orthodontic treatment policy in Tanzania.

Adolescent↗

PubMed2004

Incidence and severity of root resorption in orthodontically moved premolars in dogs.

OBJECTIVES: To study treatment-related factors for external root resorption during orthodontic tooth movement. DESIGN: An experimental animal study. SETTING AND SAMPLE POPULATION: Department of Orthodontics and Oral Biology, University Medical Centre Nijmegen, The Netherlands. Twenty-four young adult beagle dogs. EXPERIMENTAL VARIABLE: Mandibular premolars were bodily moved with continuous or intermittent controlled orthodontic forces of 10, 25, 50, 100, or 200 cN according to standardized protocols. At different points in time histomorphometry was performed to determine the severity of root resorption. OUTCOME MEASURE: Prevalence of root resorptions, defined as microscopically visible resorption lacunae in the dentin. Severity of resorption was defined by the length, relative length, depth, and surface area of each resorption area. RESULTS: The incidence of root resorption increased with the duration of force application. After 14-17 weeks of force application root resorption was found at 94% of the root surfaces at pressure sides. The effect of force magnitude on the severity of root resorption was not statistically significant. The severity of root resorption was highly related to the force regimen. Continuous forces caused significantly more severe root resorption than intermittent forces. A strong correlation (0.60 < r < 0.68) was found between the amount of tooth movement and the severity of root resorption. CONCLUSIONS: Root resorption increases with the duration of force application. The more teeth are displaced, the more root resorption will occur. Intermittent forces cause less severe root resorption than continuous forces, and force magnitude is probably not decisive for root resorption.

Analysis of Variance↗

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↗

PubMed2004

[Digital cephalometrics].

There are different methods to produce digital head films and all have advantages and disadvantages. With a digital head film and a computer programme for digital cephalometry an analysis can be performed easily. All existing computer programmes for digital cephalometry use reference values to compare with the patient's values. However, the magnification factors of the two data sets, which are compared, must be known and correction to the same magnification must be possible within the programme. Furthermore, the reference values should be age, gender, and population related. Many commercially available programmes do not fulfil these criteria. A well-designed programme for digital cephalometry should have the possibility to calculate age and gender-related reference values based on values of the target population. Furthermore it should have the possibility to analyse several longitudinal head films at the same time and to present the data graphically. A national survey among Dutch orthodontists by the end of 2000 demonstrated that 35% of Dutch orthodontists used digital cephalometry in their office. The most commonly used analysis was the Steiner-Tweed analysis, which was performed by nearly 60% of the orthodontists.

Age Factors↗

PubMed2004

[What do dental students think about their future career practice? Differences between men and women].

Aim of this study was to get more insight into the career choice, plans and expectations, and practice pattern preferences of male and female dental students in The Netherlands. A structured questionnaire was sent out to all 5th year dental students in The Netherlands in the academic year 2001/2002 (n = 258). The overall response was 65%. Both male and female students prefered working in a group practice environment rather than a solo practice, in which significant more males prefered ownership. Only 23% of the males and 7% of the females expected to work full time in the future. An important factor was leisure time, but for the female students 'taking care for children' was still decisive. The new job description 'oral physician' for the future dentist as advocated by Dutch health authorities was found less attractive than the present profession 'dentist'. Only a quarter of the females and half of the males is interested to serve as manager of a team of dental health professionals. It is concluded that male and female dental students differ in their plans and expectations with respect to their future career choices and practice pattern preferences. As the majority of the present dental students is female this will have a major impact on the dental profession.

Adult↗

PubMed2003

No justification of routine screening for 22q11 deletions in patients with overt cleft palate.

The velo-cardio-facial syndrome (VCFS), caused by a submicroscopic deletion of chromosome 22q11, is the most common syndrome that has palatal anomalies as a major feature. A possible strategy for early detection of VCFS is routine screening for 22q11 deletions in all infants with cleft palate (CP). The purpose of this study was to evaluate whether this strategy is preferable to testing on clinical suspicion. At the Nijmegen Cleft Palate Craniofacial Center, 58 new patients with overt CP were routinely tested, using fluorescence in situ hybridization (FISH), for a 22q11 deletion. One deletion was identified in a newborn girl with an overt CP who was clinically not suspected of having VCFS. Based on this study (n = 45) and the literature (n = 54), the prevalence of 22q11 deletions among children with CP, but without any other symptoms of VCFS, is estimated to be one in 99. We take the view that this figure is rather low and that early discovery will rarely have significant clinical or genetic consequences. Because CP patients remain under medical attention, almost all of the infants with isolated CP and VCFS will be recognized as having the syndrome at a later age when additional features have developed. Therefore, we conclude that routine FISH testing for 22q11 deletions in infants with overt CP is not indicated, provided clinical follow-up is guaranteed.

Abnormalities, Multiple↗

PubMed2003

Age effect on orthodontic tooth movement in rats.

Orthodontic procedures seem to be more time-consuming in adults than in juveniles. This might be related to delay in the initial tissue response or to a slower turnover of the bone and periodontal ligament in adults. To study this problem, we studied orthodontic tooth movement in two groups of 30 rats, aged 6 wks and 9-12 mos, respectively. At one side of the maxilla, 3 molars together were moved mesially with a standardized orthodontic appliance delivering a force of 10 cN. The other side served as a control. The results showed a faster initial tooth movement in juvenile than in adult animals. However, once tooth movement had reached the linear phase, the rate of tooth movement was the same in both groups. The results indicate that, besides a delay in the onset of tooth movement in adult animals, tooth movement could be equally efficient in adults once it had started.

Aging↗