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At least 1,081 records · Page 60Linked to original sources
PubMed1997

Regressive changes of the dental pulp complex in retained primary molars with congenitally missing successor teeth.

This study was undertaken to investigate the regressive changes occurring in the dental pulp complex (pulp, dentin, and cementum) of retained mandibular primary second molars with congenitally missing bicuspid teeth. Seventeen retained, caries free, primary molars were used. The specimens were fixed in 10% neutral buffered formalin. Fixed samples were decalcified, routinely prepared, embedded in paraffin, sectioned, and stained with hematoxylin and eosin. The results demonstrated a reduction in the pulp size, abnormal odontoblastic pattern, declined vascularity, pulp degeneration, pulp stones, accelerated formation of secondary dentin, and hypercementosis. This study suggests that these findings may be from aging and physiological defensive changes. These normal, age-induced changes are of considerable importance in the fields of endodontics, orthodontics, and pediatric dentistry.

Adult↗
PubMedDate not supplied

Transient red discoloration: report of case.

The different evolutions of a red discoloration of the primary maxillary central incisors in the same patient are charted. In the right central incisor the red discoloration disappeared; in the left it faded but was sustained until exfoliation. This case supports the theoretical existence of a transient type of discoloration following trauma. The resorption of posttraumatic intrapulpal bleeding in a primary tooth is discussed as a possible pathogenesis.

Child, Preschool↗
PubMed2002

Incomplete tooth fracture following root-canal treatment: a case report.

AIM: To demonstrate the need for proper restoration of root-filled teeth. SUMMARY: Tooth fracture can be a sequel to root-canal treatment. It is associated with the removal of excessive amounts of the tooth substance during the instrumentation phase, the use of unnecessary force during obturation, or inadequate planning of the design of the eventual coronal restoration to include appropriate cuspal protection. Rarely, a fracture may be present in a tooth before treatment commences, but remains undetected. A case describing incomplete vertical tooth fracture of a root-filled mandibular first molar is presented.

Adult↗
PubMed2003

The influence of wisdom tooth impaction on root formation.

UNLABELLED: The development of wisdom teeth occurs within a definite period of time. The correlation of wisdom tooth development and chronological age has been frequently used for several purposes, e. g. the start of orthodontic treatment, estimates of age or, for legal and anthropological purposes. Wisdom teeth are frequently impacted in the bone. It has been argued that the impaction of wisdom teeth can cause a delay in root development. This thesis could have bearing on age estimations in teenagers and young adults and the timing of dental treatment. The aim of this study was to determine whether the impaction of wisdom teeth influences the velocity of root formation. MATERIAL AND METHODS: The dental x-rays (orthopantomograms) of 1053 outpatients were evaluated (age: 14 to 24 years). The condition "impacted" or "not impacted" was registered for each wisdom tooth present. The impaction types were further classified. The data were then calculated using statistical tools. RESULTS: The correlation between the developmental stages of wisdom teeth and the chronological age is high. However, neither any impaction type nor the whole group of retained wisdom teeth showed a statistically significant different course of root development compared to the root development of non-retained wisdom teeth. DISCUSSION: This study provides evidence for the lack of bearing of wisdom teeth topography on the growth stages of the dental roots within definite time intervals, based on the evaluation of orthopantomograms only. Obviously, the variations of root formation in the selected chronological periods are greater than the variations attributable to possible periods of delay in root formation of retained wisdom teeth. These results could have some importance for the fields of dental anthropology and dentistry.

Humans↗
PubMed1994

Changes in patient age and tooth distribution for root canal treatment in a teaching hospital over a 15-year period.

This study was undertaken to determine the changing pattern of root canal treatment undertaken by undergraduates in a teaching hospital over a period between 1976 and 1990 in terms of the incidence of root canal treatment, noting particularly changes in the types of tooth treated and in the age distribution of patients receiving treatment. It was found that the pattern of provision of root canal treatment has altered in recent years to involve a greater proportion of multi-rooted posterior teeth. More treatment is also being provided for older patients. The trends are comparable with those that have occurred in general dental practice.

Adult↗
PubMed2003

Constant versus dissipating forces in orthodontics: the effect on initial tooth movement and root resorption.

The aim of this clinical and confocal laser scanning microscopic study was to compare the effects of two frequently used archwires on tooth movement and root resorption. A total of 84 premolars in 27 individuals (10 boys, 17 girls, with a mean age of 12.5 years) was moved buccally with an experimental fixed orthodontic appliance. In a split mouth experimental design the premolar on one side was activated with a stainless steel wire with a buccal offset of 1 mm, which was reactivated every four weeks and the contralateral premolar was moved with a superelastic wire with a force plateau of 0.8-1 N. This wire had an initial activation of 4.5 mm and was not reactivated during the 12-week experimental period. At the end of the experimental period the teeth were extracted. Six premolars were used as control teeth and were extracted before the experiment started. Tooth displacement was studied three-dimensionally on dental casts with a co-ordinate measuring machine. The depth, perimeter, area, and volume of the resorption lacunae was measured using three-dimensional digital images made with a confocal laser scanning microscope (CLSM). On these images the resorbed portions of the root surface were 'reconstructed' mathematically. The results show that the teeth activated with the superelastic wire moved significantly more than the teeth with the steel wire during the experimental period. The depth of the resorption lacunae did not differ significantly between the groups; however, perimeter, area, and volume of the resorption lacunae on the teeth of the 'superelastic group' were 140 per cent greater than on the teeth of the 'steel group'. It may be concluded that a greater amount of tooth movement occurred with superelastic wires, offering a force level of 0.8-1 N compared with stainless steel wires, with initially higher but rapidly declining forces in an experimental set up for a period of 12 weeks. The amount of root resorption was significantly larger in the superelastic group.

Adolescent↗
PubMed1996

Effects of a doubled orthodontic force magnitude on tooth movement and root resorptions. An inter-individual study in adolescents.

The aim of this clinical and histological study was to compare the effects of two controlled, continuous forces of 50 cN (approximately 50 g) and 100 cN (approximately 100 g) on tooth movement and root resorptions. The patients, consisting of 32 individuals, 14 boys and 18 girls (mean age 13.1 years), were divided into four groups of eight individuals. The experimental periods were 4 and 7 weeks. In this investigation, designed as an inter-individual study, only the maxillary first premolar on the right side was utilized. The test tooth was buccally moved by means of a fixed orthodontic appliance. A continuous, weekly controlled force of 50 cN was applied to 16 premolars and a force of 100 cN to the remaining 16 test teeth. The force declined on average 22 per cent during the first week when 50 cN was applied and 27 per cent when 100 cN was applied. Tooth movements were studied on dental casts using a coordinate measuring machine. After 4 and 7 weeks, the tooth movements ranged between 0.5 and 3.4 mm (4 weeks) and 2.7 and 7.1 mm (7 weeks) for 50 cN and between 1.0 and 2.9 mm (4 weeks) and 2.2 and 8.3 mm (7 weeks) for 100 cN, with no significant difference when the force magnitude was doubled. Root resorptions were registered in histological sections in all experimental teeth, more frequently after application of 50 cN compared with 100 cN after 7 weeks. However, the severity of root resorption (extension and depth of resorbed root contour and size of root area on histological sections) did not differ significantly when the applied force was doubled to 100 cN. Great individual variations were noted regarding both the magnitude of tooth movement and amount of root resorption.

Adolescent↗
PubMed1999

Immunofluorescence detection of cadherins in mouse tooth germs during root development.

The distribution of two cell-adhesion molecules, E- and P-cadherin, was studied in relation to morphological changes in Hertwig's epithelial root sheath Before root dentinogenesis had started, the root sheath expressed both cadherins. As dentinogenesis proceeded, the sheath fragmented and lost P-cadherin rapidly and E-cadherin slowly, whereas the intact sheath at the apical end continued to express both. These results suggest that the two cadherins play a part in root as well as in crown development, and indicate that the decrease in the amount of these molecules and the fragmentation of the epithelial root sheath are interrelated.

Animals↗
PubMed1989

["Endo-prosthetic" preparation of curved roots].

During the tooth preparation for root posts, all must be attempted to avoid weakening of the root. This "must" is rather easy for straight roots, but the same is not true of curved roots. The authors have used the method described by BRAMANTE et al. to study the effects of various techniques of instrumental sequences of endodontic preparation, and of two instrumental sequences of root post preparation. From this studies, it results that: --the respect of the canal path during the endodontic phase conditions the respect of the internal wall of the curvature, during drilling. --among the four endodontic techniques studied: MM 3000, Step-Back, Anti Curvature Filling and Canal Finder System, the last two seem to allow more respect of the canal path. --the instrumental sequence using Largo drills to prepare a canal, presents two types of drawbacks: * Excessive abrasion of the convex (internal) wall of the canal system. It seems that the blunt point rests against the concave portion of the canal and pushes the drill toward the internal wall, therefore weakening it. * Inadequate match between the size of the drill and that of the prepared canal. --the Parapost drills, on the contrary, respect the endodontic path, and may even be used beyond the curvature (2 mm). Besides, the diameter of the prepared canal is similar to that of the instrument used. These two factors permit to obtain a better retention of the post as well as a lesser weakening of the root.

Dental Pulp Cavity↗
PubMed1998

Gene expression of growth and differentiation factors-5, -6, and -7 in developing bovine tooth at the root forming stage.

Growth and differentiation factors (GDF)-5, -6, and -7 are members of the bone morphogenetic protein (BMP) family. Previous studies suggest their importance in bone development and in tendon/ligament morphogenesis. The cells of the dental attachment apparatus, cementum, periodontal ligament, and alveolar bone proper are derived from the dental follicle proper. In this study, we investigated the expression of GDF-5, -6, and -7 genes in tissues of the bovine incisor tooth germ at the root forming stage. The results demonstrate distinct expression of GDFs in both the dental follicle and the odontoblast layer. While GDF-5 and -6 mRNAs were expressed in both the dental follicle and the odontoblast layer, GDF-7 mRNA expression was detected only in the dental follicle. These results indicate that GDFs, expressed in the bovine tooth germ including the dental follicle, may be potent regulatory molecules in the development of the dental attachment apparatus.

Amino Acid Sequence↗