Biomedical subjects

L C Martens

Publications and source records attributed to L C Martens.

At least 19 recordsLinked to original sources

PubMed2006

Abnormal dentin structure in two novel gene mutations [COL1A1, Arg134Cys] and [ADAMTS2, Trp795-to-ter] causing rare type I collagen disorders.

Histological and ultrastructural observations of dentin of two patients affected with rare types of type I collagen disorders are presented. In the first case, a homozygous nonsense mutation in ADAMTS2 (substitution of a codon for tryptophan by a stopcodon) causes type VIIC Ehlers-Danlos syndrome (EDS) with multiple tooth agenesis and focal dysplastic dentin defects. In the second case, a missense mutation in COL1A1 (substitution of arginine by cysteine) results in a type I EDS phenotype with clinically normal-appearing dentition. Tooth samples are investigated by using light microscopy (LM), transmission electron microscopy (TEM) and immunostaining for types I and III collagen, and tenascin. These are compared with samples from patients with types III and IV osteogenesis imperfecta (OI) in association with dentinogenesis imperfecta (DI), showing a consistently abnormal appearance of the dentin in all specimens, with variations being primarily those of degree of change. Similarities in histological changes include the alternating presence of normal and severe pathological areas in primary and secondary dentin, the latter being characterized by large canal-like structures in atubular areas. Ultrastructural evidence of pathological dentinogenesis include abnormal distribution, size and organization of collagen fibers, which may also be found in clinically unaffected teeth. The histological and ultrastructural changes seen can be explained on the basis of odontoblast dysfunction which may be secondary to the collagen defect, interfering with different levels of odontoblast cell function and intercellular communication. These observations on (ultra)structural dentin defects associated with the two novel gene mutations are the first ever reported.

Collagen Type I↗

PubMed2006

Seckel syndrome associated with oligodontia, microdontia, enamel hypoplasia, delayed eruption, and dentin dysmineralization: a new variant?

Seckel syndrome (SCKL) [OMIM Entry 210600] is a rare, autosomal recessive syndrome, characterized by severe intrauterine and postnatal growth retardation, microcephaly, mental retardation, and typical facial appearance with beaklike protrusion of the midface (bird-headed). Associated findings may include limb anomalies, dislocation of femoral heads, scoliosis, and gastrointestinal malformation. A 14-year-old boy is presented with brain hypoplasia, pachygyria, hydrocephaly, enamel hypoplasia and root dysplasia in the temporary dentition, and oligodontia, severe microdontia, and delayed eruption of the permanent dentition. The association of SCKL with the above unusual dental findings may represent a new phenotype.

Abnormalities, Multiple↗

PubMed2005

Dentinogenesis imperfecta associated with short stature, hearing loss and mental retardation: a new syndrome with autosomal recessive inheritance?

The follow-up history and oral findings in two brothers from consanguineous parents suggest that the association of dentinogenesis imperfecta (DI), delayed tooth eruption, mild mental retardation, proportionate short stature, sensorineural hearing loss and dysmorphic facies may represent a new syndrome with autosomal recessive inheritance. Histological examination of the dentin matrix of a permanent molar from one of the siblings reveals morphological similarities with defective dentinogenesis as presenting in patients affected with Osteogenesis Imperfecta (OI), a condition caused by deficiency of type I collagen. A number of radiographic and histological characteristics, however, are inconsistent with classical features of DI. These findings suggest that DI may imply greater genetical heterogeneity than currently assumed.

Body Height↗

PubMed2005

Self-mutilation behaviour in Lesch-Nyhan syndrome.

Lesch-Nyhan syndrome (LNS), first described in 1964 by Lesch and Nyhan, is a rare X-linked genetic disorder involving (near) absence of the enzyme hypoxanthine-guanine phosphoribosyl transferase (HPRT). It occurs in 1:100,000 to 380,000 live births (1, 2). The deficiency of HPRT activity leads to an excessive uric acid production resulting in neurological, renal and musculoskeletal manifestations. Death usually occurs in the second or third decade from infection or renal failure. Clinical presentation is characterized by mental retardation, choreoathetosis, spasticity, hyperuricemia and cerebral palsy. A characteristic feature of LNS is the appearance of intractable self-injurious behaviour (SIB), usually in the form of severe lip and finger biting, gouging of eyes, face scratching and head banging requiring extreme management techniques such as the application of restraints and or extraction of teeth at an early age. In this case report a unique approach of SIB in LNS is presented.

Bites, Human↗

PubMed2004

Early Childhood Caries (ECC): what's in a name?

AIM: It is evident from the number of published scientific papers on Early Childhood Caries (ECC) that interest in this problem has grown in recent years. Many authors have been trying to devise a clear definition or classification for ECC. The aim of this review was to inventory the prevalence of ECC and to seek a consensus regarding definition and diagnosis. Further attention was paid to the aetiological factors including the role of microrganisms. Finally, education, parenting and treatment procedures were discussed. METHODS: For this review, epidemiological studies on caries prevalence in children aged between 0 and 36 months were compiled through a systematic approach using Medline. REVIEW: This clearly showed that ECC continues to be a serious public health problem and that there is a great variety of definitions and diagnoses used worldwide, reflected in the prevalence data. This review confirms the multicausal aetiology and the need for further research. The authors strongly support the recommendations formulated at the workshop in Bethesda 1999, and the policy statements by the AAPD. CONCLUSION: More efforts should be made to reach the high risk groups within populations, in order to reduce the prevalence of ECC and S-ECC (Severe Early Childhood Caries) and consequently to ameliorate the quality of life of these children. Long-term intervention studies are required for the evaluation of these efforts.

Child↗

PubMed2004

Oral health and habits in children with asthma related to severity and duration of condition.

AIM: This study was designed to examine the oral health status of asthmatic children and to compare the oral health condition and habits of different groups of asthmatic children. METHODS: 140 asthmatic children were involved in the present study. Of those, 30 were younger than 7 years of age, 73 were between 7 and 12, 37 were older than 12. Dental caries was scored according to the guidelines of the BASCD. No radiographs were taken. The gingival health and the amount of plaque were assessed using the bleeding index described by Mühleman and Son [1971] and the plaque index of Silness and Löe [1964] respectively. To differentiate between the asthmatic children three explanatory variables were used: the time the asthmatic symptoms had lasted, the exposure time to the medication and the severity of the asthmatic condition. Finally the parents and children were asked to fill in a questionnaire referring to oral health habits. RESULTS: The mean dmft was 1.99 (SD+/-2.74) and the mean DMFT was 1.10 (SD+/-1.98). Non-parametric correlation and multiple logistic regression analyses showed no significant difference between the caries (dmft/s, DMFT/S), the gingival health (bleeding index) and plaque indices and the three explanatory variables. The impact of possible compensatory factors as oral hygiene and dietary habits was of no significant importance. CONCLUSION: This analysis revealed that neither the period (of the disease and the medication) nor the severity of the asthma had a significant influence on the risk of caries and gingivitis in asthmatic children. No reported oral health and dietary habits could explain this lack of correlation.

Adolescent↗

PubMed2003

Unusual oral findings in dermatosparaxis (Ehlers-Danlos syndrome type VIIC).

A 13-year-old patient with dermatosparaxis (Ehlers-Danlos syndrome type VIIC), an autosomal recessive disorder of procollagen-I-N-proteinase, is presented. The oral findings comprise micrognathia, hypodontia, localized microdontia, opalescent tooth discoloration, root dysplasia, pulp obliteration, severe gingival hyperplasia, frontal open bite, and severe restriction of TMJ mobility. The reported anomalies suggest the need for expanding the present phenotypic spectrum. This is the first report on oral findings in the syndrome.

Adolescent↗

PubMed2003

Judgement criteria for molar incisor hypomineralisation (MIH) in epidemiologic studies: a summary of the European meeting on MIH held in Athens, 2003.

AIM: This paper reviews the proceedings and conclusions of a meeting of experts concerned with the problem of hypomineralised incisors and molars (MIH). The aims of this meeting were to establish criteria for the judgement of MIH, to select representative cases and to discuss how the name of the condition was best described as hypomineralised, or hypomaturated, first permanent molars. CONCLUSION: There was not complete agreement as to the correct diagnosis and aetiology of the condition. A suggested list of definitions of the judgement criteria to be used in diagnosing Molar Incisor Hypomineralisation (MIH) for prevalence studies was agreed upon.

Child↗

PubMed2002

Oral hygiene habits and oral health in cystic fibrosis.

AIM: The present study was designed to investigate oral hygiene habits and fluoride use in cystic fibrosis (CF) homozygotes, heterozygotes and healthy controls as a function of caries experience (DMF-T) and oral cleanliness (dental plaque, dental calculus and gingival bleeding). METHODS: Oral hygiene habits in CF homozygotes (n=42), heterozygotes (n=48) and healthy controls (n=62) were used in a multivariate analysis with caries experience (DMF-T) and oral cleanliness (dental plaque, calculus and gingival bleeding) as response variables. RESULTS: CF homozygotes had a significantly lower caries experience (p< or =0.001) and less gingival bleeding sites (p< or =0.02). Oral hygiene habits were not significantly different between the three groups, except for intake of fluoride supplements. Significantly more CF homozygotes had received fluoride supplements. Oral hygiene habits did affect caries experience or oral hygiene differently in each study group. CONCLUSION: No matter what oral hygiene habits were, CF homozygotes had an overall better oral health status. Apparently they seemed to possess intrinsic salivary compensatory mechanisms, as the significant higher use of fluoride supplements appeared not to be responsible for the better oral health.

Journal Article↗

PubMed2001

Parental occupational status related to dental caries experience in 7-year-old children in Flanders (Belgium).

OBJECTIVES: The study aimed to investigate differences in the oral health of 7-year-old Flemish children by the parents' occupational class and to explore behavioural and demographic factors linked to social inequalities in oral health. PARTICIPANTS: A stratified cluster sample of 1,500 primary school children in Flanders, born in 1989. METHOD: The clinical oral examination was performed in the first year of a longitudinal oral health project in Flanders (1996-2001) by 16 calibrated examiners. Information on occupational level of the parents and on oral health related behaviour was gained, respectively, by the school health care centres and the parents of the children using a structured questionnaire. RESULTS: The mean dmf values between the several SES groups, assessed by occupational status of the parents, were significantly different (P<0.001). The mean dmft and dmfs values were the lowest for the most advantaged children (1.3/2.7) and were threefold higher in the least advantaged children (3.9/9.1). The prevalence of caries-free children was 2.5 times higher among the highest SES families compared with the lowest SES families. In a logistic regression model adjusted for the stratification factors, the excess risk for caries in children increased with decreasing occupational level of the parents. There was a cumulative effect of decreasing occupational level and oral health habits on the caries prevalence. CONCLUSION: The results of the study allow the supposition that social inequalities in oral health among children exist in Flanders. Environmental factors and individual behavioural factors partially explain why social class might influence oral health.

Belgium↗

PubMed2000

Effect of maturation on the fluoride release of resin-modified glass ionomer and polyacid-modified composite resin cements.

The effect of an early water contact on the fluoride release is studied for the resin-modified glass ionomer cements (RM-GIC) GC Lining LC, PhotacBond, Vitremer and Vitrebond and for the polyacid-modified composite resins (PAM-C) Variglass and Dyract. Six months fluoride release profiles were determined in regularly renewed water (37 degrees C), for the products directly after light curing and after 24 h maturation in a humid atmosphere (85% RH). ANOVA shows that both the short-term and the long-term fluoride release of a RM-GIC are influenced by this maturation. This indicates that direct water contact for this material should be avoided. For the RM-GIC a correlation is found between the initial fluoride release process and the long-term process. For the PAM-C materials, no differences in the fluoride release are found as a function of maturation, indicating that early water contact has no effect. The amounts of fluoride released by PAM-C are low compared to RM-GIC, which can affect their caries preventive potential. The results are explained on the basis of the setting reaction of both types of materials.

Acrylic Resins↗

PubMed2000

Effect of a neutral citrate solution on the fluoride release of resin-modified glass ionomer and polyacid-modified composite resin cements.

The effect of 0.01 mol/l citrate solution at pH = 7 on the fluoride release is compared for the resin-modified glass ionomer cements (RM-GIC) GC Lining LC, PhotacBond, Vitremer and Vitrebond and for the polyacid-modified composite resins (PAM-C) Variglass and Dyract by means of the six-month fluoride release profiles at 37 degrees C. The fluoride release of both RM-GIC and PAM-C increases in the neutral citrate solution as compared to water, which can be explained by the ability of citrate to complex metal ions and hence to degrade the glass as well as the polysalt matrix of the cement. Although RM-GIC release more fluoride than PAM-C in water as well as in citrate solution, the relative increase in fluoride release upon immersion in citrate solution is most pronounced for PAM-C. Whereas for the latter citrate affects both the short-term and long-term fluoride release, for RM-GIC only the long-term fluoride release is affected. This suggests that the action of citrate increases with decreasing importance of the polysalt formation in the hardening of the material. This could be explained on the basis of the difference in the chemical properties of the cement matrix.

Acrylic Resins↗

PubMed2000

Fluoride release profiles of mature restorative glass ionomer cements after fluoride application.

This study investigates the fluoridation of four conventional glass ionomer cements (GIC) (ChemFil Superior encapsulated, Fuji Cap II, Ketac-Fil and Hi Dense) and three resin-modified GIC (RM-GIC) (Fuji II LC encapsulated, Photac-Fil and Vitremer). The fluoride release of matured restorative GIC was measured as a function of time, after four repeated fluoridations in a 2% NaF aqueous solution for 1 h. This release was corrected for the intrinsic release as determined with a control group. It was demonstrated that application of fluoride is capable of recharging GIC but the subsequent high fluoride release only lasts for one or a few days. Moreover, the fluoride release behaviour depends on the cement formulation. Comparable to the intrinsic release, the net fluoride release after fluoridation is composed of a short- and a long-term process, the former being predominant after fluoridation. The total amount of fluoride released according to the short-term process increases with consecutive fluoridations. This is especially pronounced for the RM-GIC, who exhibit a relatively slow release after fluoridation as compared to the conventional GIC. An explanation for these results is suggested on the basis of the physicochemistry of the setting reaction of the cements and of the fluoridation process.

Capsules↗

PubMed2000

A multidisciplinary treatment approach to a complicated maxillary dental trauma: a case report.

This case report describes the treatment of an 18-year-old male who lost two central maxillary incisors due to dental trauma. Because of a deep overbite and serious occlusal instability, the lost teeth 11 and 21 could not be replaced by a conventional fixed prosthesis. The vertical dimension of occlusion was increased using a Hawley-type appliance over a period of 1 year. When sufficient intermaxillary space was gained the alveolar ridge was augmented with a mandibular symphysis graft. Nine months later two one-stage non-submerged implants (ITI, Straumann, Waldenburg, Switzerland) were inserted. After further soft tissue adaptation to two temporary acrylic crowns, porcelain veneers were placed on the two implants and the lateral incisors.

Adolescent↗

PubMed1999

Accuracy of four electronic apex locators: an in vitro evaluation.

In the present study, the accuracy and operator dependency of four electronic canal length measuring devices (Apex Finder AFA Model 7005, Apex-Finder, Neosono Ultima EZ and Apit 2) were compared under a set of specified conditions. The electronic apex locators were tested in unflared dry, flared wet and flared dry canals, and in a gelatin as well as in a sodium hypochlorite sponge model. Fifteen extracted single-canaled teeth were selected. The differences between canal lengths obtained by the electronic apex locators and actual canal lengths were scored. Only the Apex-Finder was found to be unreliable (measurements higher than +/- 0.5 mm from the apical foramen). This device was also found to be particularly dependent on operator. A ranking based on a precision of +/- 0.1 mm from the apical foramen showed the Apex Finder AFA Model 7005 to be the most accurate. Early coronal flaring did not ensure better or more precise readings. The gelatin model was evaluated to be more suitable for testing electronic apex locators in vitro than the sodium hypochlorite model.

Analysis of Variance↗

PubMed1999

Apical microleakage after lateral condensation, hybrid gutta-percha condensation and Soft-Core obturation: an in vitro evaluation.

The purpose of the present study was to evaluate the apical seal of root canals filled with a cold lateral condensation, a hybrid gutta-percha condensation technique and with Soft-Core obturators. Three groups of 35 maxillary anterior teeth and four control anterior teeth were treated with a crown-down/step-back technique. All roots were submerged in India ink for 1 week. The roots were cleared and the degree of linear dye penetration was measured. The mean apical leakage for the Soft-Core technique was at least twice as extensive as for the two other gutta-percha obturation techniques. No statistically significant differences were found between the two other condensation techniques.

Dental Leakage↗

PubMed1998

[Mechanism of action of fluorides in local/topical application].

The marked caries reduction in many countries over the last two decades is thought to be mainly the result of the widespread and frequent use of low concentrations of fluorides mainly via toothpastes. This article gives a review on fluoride sources in the oral cavity and discusses the physiochemical mechanisms by which fluoride interacts with enamel during the caries process and its reversal. From this review it becomes clear that fluoride incorporated into the enamel mineral during tooth development has little effect on the caries process. It is the fluoride incorporated posteruptively and in the aqueous phase during the caries challenge that is of primary importance. The most effective caries preventive fluoride regimen, both from a theoretical perspective and as proved clinically, is the frequent (daily) low concentration application of fluoride from toothpastes and/or mouthrinses. High concentrations, however, used at intervals of months or years and administered by the dentist, work initially not only on both de- and remineralisation, but also by providing fluoride as calcium-fluoride or absorbed in early lesions which is subsequently available over prolonged periods.

Calcium Fluoride↗

PubMed1998

[Use of fluorides in children: recommendations of the European Academy for Pediatric Dentistry].

The European Academy of Paediatric Dentistry (EAPD) strongly endorses that fluoride use should be part of any preventive programme for the control of dental caries in children. Each child under the care of a dentist should have a carefully planned programme appropriate to the level of caries risk and age of each child. Such a preventive programme should be reevaluated at least every six or 12 months and changed according to the patient's risk and the improvement or not of his or her's overall health. It is the combination of the use of an appropriate fluoride toothpaste with good oral hygiene that is the key to good dental health. This policy document deals with guidelines for systemic use of fluorides, fluoride supplements, topical methods (varnishes, mouthrinses and gels) and toothpastes. Moreover some recommendations are given to toothpaste manufacturers.

Age Factors↗