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At least 1,063 records · Page 59Linked to original sources
PubMed2003

Traumatic injuries to permanent anterior teeth among 12-year-old schoolchildren in Jordan.

OBJECTIVES: To assess the prevalence and related factors of incisor trauma among 12-year-old Jordanian schoolchildren. DESIGN: Cross-sectional study among schoolchildren. A sample of 1.878 schoolchildren aged 12 years, 940 boys and 938 girls, were randomly selected from 128 schools in urban and rural areas. Ellis classification was used to record the dental injuries on incisors. RESULTS: Of the children examined 13.8% showed dental trauma. Difference in prevalence between boys (17.1%) and girls (10.6%) was statistically significant (p < 0.05). Maxillary central incisors were the most affected (79.2%) and the most common type of crown injury was enamel-dentin fracture (40.6%). The relationship between dental injuries and socio-economic indicators was not statistically significant. There was a tendency for children with an incisal overjet greater than 5.0 mm to have experienced dental injuries (p < 0.01). Treatment need due to dental injuries was very high but less than untreated damage. CONCLUSION: The prevalence of traumatic injuries to permanent incisors in 12-year-old Jordanian schoolchildren was close to that found in other countries. Being a boy and having overjet greater than 5.0 mm were significant predisposing factors to dental injuries.

Chi-Square Distribution↗
PubMed2002

Evaluation of maxillary molar distalization with the distal jet: a comparison with other contemporary methods.

Maxillary molar distalization is an increasingly popular option for the resolution of Class II malocclusions. This communication describes the effects of one particular molar distalizing appliance, the distal jet, in a sample of 20 consecutively treated and growing subjects (11 females, nine males; mean starting age of 13) and compares these effects with those of similar devices. Pre- and postdistalization cephalometric radiographs and dental models were analyzed to determine the dental and skeletal effects. The distal jet appliances were constructed using a biomechanical couple to direct the distalizing force to the level of the maxillary first molar's center of resistance. The distal jet was the only appliance used during the distalization phase of treatment. Examination of the cephalometric tracings demonstrated that the crowns of the maxillary first molars were distalized an average of 3.2 mm into a Class I molar relationship. In the process, the first molars were tipped distally an average of 3.1 degrees, however, the amount of tipping in each case was influenced by the state of eruption of the second molar. In subjects whose second molars had erupted only to the level of the apical third of the first molar roots, distal tipping was almost twice that seen when the second molar had completed their eruption. Anchorage loss measured at the first premolars averaged 1.3 mm, but the crowns tipped 3.1 degrees distally because of the design of the appliance. The maxillary incisors were proclined an average of 0.6 degrees with minimal effect on the mandibular plane angle and lower facial height. This study suggests that the distal jet appliance effectively moves the maxillary molars distally into a Class I molar relationship with minimal distal tipping, however, some loss of anchorage is to be expected during this process. The distal jet appliance compares favorably with other intraoral distalization devices and with mechanics featuring mandibular protraction for the resolution of patients with Class II, despite the fact that these types of mechanics address different jaws.

Adolescent↗
PubMed2006

Traumatic intrusion of permanent teeth. Part 3. A clinical study of the effect of treatment variables such as treatment delay, method of repositioning, type of splint, length of splinting and antibiotics on 140 teeth.

A prospective study of 140 intruded permanent teeth was examined for the following healing complications: pulp necrosis (PN), root resorption (RR; surface, inflammatory and replacement resorption), and defects in marginal periodontal bone healing (MA). The occurrence of these healing complications was related to various treatment factors such as treatment delay, method of repositioning (i.e. expecting re-eruption, orthodontic reposition and surgical reposition), type of splint (rigid, semirigid and flexible), length of splinting (days) and the use of antibiotics. Treatment delay, i.e. before and after 24 h, had no effect upon healing. Active repositioning in individuals with incomplete root formation (surgical or orthodontic) had a negative effect upon the three healing parameters compared with spontaneous eruption. In teeth with complete root formation and an age of 12-17 no repositioning was still the best treatment in regard to MA. In individuals older than 17 years of age, cases were not anticipated to spontaneously erupt and in these cases, the general choice of treatment was either active orthodontic or surgical repositioning. The former procedure appeared in this treatment scenario to slightly reduce the risk of MA complications. However, this treatment procedure was also found to be more time demanding (an average of 22 consultations for orthodontic repositioning compared with 17 consultations for surgical repositioning). If a surgical repositioning was performed, the type of splint (i.e. flexible, semirigid or rigid) appeared to have no significant effect on the type of healing. The same applied to the length of splinting time (shorter or longer than 6 weeks). No effect of dentin covering procedures for associated crown fractures (enamel-dentin fractures) could be demonstrated. Likewise, antibiotics had no apparent effect upon healing. In conclusion, in patients with intruded teeth with incomplete root formation, spontaneous eruption should be expected. In patients with completed root formation and with an age of 12-17 spontaneous eruption can still occur, but must be monitored very carefully. In older patients (i.e. >17 years) with completed root formation, either surgical or orthodontic extrusion should be attempted. The latter procedure appeared to lead to a slight reduction (not significant) in the risk of MA complications. The extent and direction of the intrusion may however favour surgical repositioning.

Adolescent↗
PubMed2000

Bacteria of asymptomatic periradicular endodontic lesions identified by DNA-DNA hybridization.

Possible inclusion of contaminant bacteria during surgery has been problematic in studies of periradicular lesions of endodontic origin. Therefore, in this study, two different surgical techniques were compared. A second problem is that some difficult to cultivate species may not be detected using bacteriological methods. Molecular techniques may resolve this problem. DNA-DNA hybridization technology has the additional advantage that DNA is not amplified. The purpose of this investigation was to determine if bacteria from periradicular endodontic lesions could be identified using DNA-DNA hybridization. A full thickness intrasulcular mucoperiosteal (IS) flap (n = 20) or a submarginal (SM) flap (n = 16) was reflected in patients with asymptomatic apical periodontitis. DNA was extracted and incubated with 40 digoxigenin-labeled whole genomic probes. Bacterial DNA was detected in all 36 lesions. Seven probes were negative for all lesions. In patients with sinus tract communication, in teeth lacking intact full coverage crowns, and in patients with a history of trauma 4-13 probes provided positive signals. Seven probes were positive in lesions obtained by the IS, but not the SM technique. Two probes were in samples obtained with the SM technique, but not the IS. Only Bacteroides forsythus and Actinomyces naeslundii genospecies 2 were present in large numbers using either the IS or the SM technique. The SM flap technique, in combination with DNA-DNA hybridization, appeared to provide excellent data pertaining to periradicular bacteria. These results supported other studies that provide evidence of a bacterial presence and persistence in periradicular lesions.

Actinomyces↗
PubMed1999

Response of dental follicular cells to the exposure of denuded enamel matrix in rat molars.

Recent studies have indicated that cementum formation can be induced when dental follicular cells are exposed to enamel matrix. The purpose of the present investigation was to study this cementum formation and the appearance of the cells involved, including their expression of collagen types alpha1(I), alpha1(II) and alpha1(III) mRNAs, during this process by means of light microscopy and in situ hybridisation. The mandibular first molars of 5-d-old rats were surgically taken out, their enamel epithelium was removed, and then the crowns were re-inserted with the occlusal surface downwards in their crypts to allow the follicular cells to come in contact with the denuded enamel matrix. After observation periods of 2-14 d, the teeth were prepared for light microscopic examination and in situ hybridisation. A monolayer of follicular cells in contact with the exposed enamel matrix changed their morphology and increased their expression of collagen type I mRNA as early as 2-4 d after exposure to the enamel matrix. A cementum-like tissue was formed at the surface of the enamel matrix. Collagen type II mRNA was never expressed in the tissues studied, whereas collagen type III mRNA was weakly expressed in the follicular cells throughout the experiment.

Amelogenesis↗
PubMed1996

Rate of mesial translation of mandibular molars using implant-anchored mechanics.

Retromolar dental implants served as anchorage to close first molar extraction sites in five adult patients. Rates of unidirectional space closure for mandibular second molars were assessed with periapical radiographs superimposed on anatomical landmarks and retromolar anchorage implants. Regression analysis revealed that mesial displacement of the midroot area of the leading root was less variable (r = 0.97) than for other landmarks on the same teeth: crown (r = 0.83), alveolar crest (r = 0.82) or apex (r = 0.90). When mesial root movement (uprighting) was the principal feature of the initial mechanics (4 of the 5 patients), mesial movement of the apex was about 0.60 mm/mo for the first 8 months and then decreased to about 0.34 mm/mo as the trailing (distal) root of the second molar engaged the relatively dense bone formed by the leading (mesial) root. During the last year of space closure, radiolucent foci were noted 1-2 mm ahead of the distal root. These data suggest: (1) sustained orthodontic translation is a physiological manifestation of bone modeling and remodeling throughout the adjacent alveolar process, and (2) rate of mandibular molar translation is inversely related to the apparent radiographic density of the resisting alveolar bone.

Adult↗
PubMed2000

Dental erosion in Cuban children associated with excessive consumption of oranges.

Marked erosion at the mesial edges of upper front teeth was observed during an examination of Cuban children. The preferential erosion of mesial edges produced characteristic V-shaped defects on upper central incisors, and the aim of the present study, carried out on 12-yr-old children (N = 1010) in 10 communities in the Province of Havana was to establish the frequency of dental erosion and explain its occurrence. The symmetrical erosion of teeth 11 and 21 (excluding crown injuries and attrition) were clinically classified into four grades: 0.5 = objectionable; 1 = abnormal mesial shortening of incisal edges; 2 = V-shaped defect of cutting edges; 3 = exposure of dentine and extension of the erosive defect to the lateral incisors. In four of the communities, children did not show or rarely showed incisal erosion. In the other six communities, the frequency was surprisingly high (16.6-40.9%). Overall, 17.4% of children exhibited erosion, and the occurrence was significantly higher in girls (20.7%) than in boys (15.0%). The typical V-shaped pattern of erosion seems to be a consequence of the manner in which citrus fruits are eaten. There was also a positive correlation between the frequency of dental erosion and the proximity of citrus plantations, which presumably related to the extent of (daily) orange consumption.

Adolescent↗
PubMed1997

A retrospective evaluation of traumatized permanent teeth.

The purpose of this retrospective study (15 years follow-up) was to evaluate the long-term results of treatment to injured teeth following acute trauma. A total of 198 patients with 488 injured teeth were available for analysis. Uncomplicated crown fractures were restored with composite restorations in 106 teeth. 19% of the restorations had been replaced more than 10 times and at the final examination approximately 25% were rated as unacceptable, i.e. needing clinical treatment. Fixed prosthetic therapy had been provided for 106 teeth and endodontic treatment had been provided in 114. Colour changes appearing at late stage suggested obliteration, necrosis or endodontically treated teeth. Anterior composite restorations have been considered acceptable as semi-permanent restorations in patients of early school age (7-15 years), and may have been an advance on what was possible previously, but results of this clinical study suggest that they still do have major shortcomings. There remains a need for a simple, conservative method of restoring aesthetics to fractured and discoloured anterior teeth for clinical use in young patients of late school age.

Acute Disease↗
PubMed1997

Comparative analysis of transforming growth factor-beta isoforms 1-3 in human and rabbit dentine matrices.

Previous studies have implicated transforming growth factor-beta (s)(TGF-beta) in both development. Here TGF-beta isoforms in dentine extracellular matrix were analysed because these molecules may participate in dental issue repair. EDTA-soluble and collagenase-released fractions were isolated from human crown and root and rabbit incisor dentine samples and analysed for TGF-beta isoforms. TGF-beta(1) was the major isoform detected in all samples and the only isoform detected in human dentine samples. TGF-beta(2) was detected only in the collagenase-released fraction of rabbit incisor dentine and was present at low levels. TGF-beta(3) was detected in both EDTA-soluble and collagenase-released fractions of rabbit dentine. Greater levels of the TGF-beta(1) isoform were detected in the rabbit than human dentine samples and some differences in distribution amongst the two tissue fractions were observed between these species. The presence of these isoforms of TGF-beta in dentine may provide a reservoir of growth factor in the matrix that could participate in processes leading to tissue repair after injury.

Animals↗
PubMed2001

Factors affecting the time of onset of resorption in avulsed and replanted incisor teeth in children.

Resorption is the main reason for loss of replanted teeth. The outcome examined in this study is the timing of the onset of resorption. The effect of dichotomised dry and wet time intervals as well as the presence of additional crown damage and of contamination were determined. Of 84 replanted teeth, 67.5% developed resorptions. Twenty-eight had detectable additional crown damage with a more rapid onset being seen in these cases (P=0.009). The critical limit for dry time was 15 min (P=0.038) and significant differences persisted for greater limits also. Serial analysis of the association between the time of onset of root resorption and dichotomised wet time variables failed to yield any significant associations. There was visible contamination detected in 32 teeth and these exhibited a more rapid onset of resorption than the other cases (P=0.030). Teeth with inflammatory root resorption (12.8%) had a more rapid onset of resorption than those that developed replacement resorption (54.7%) (P<0.001). It is concluded that the risk of early resorption is increased in teeth that have additional damage or have contamination, or are kept in dry conditions for longer than 15 min.

Adolescent↗
PubMed1997

The effects of immunoglobulins on the convective permeability of human dentine in vitro.

Immunoglobulin molecules are localized in the dentinal tubules of non-carious and carious teeth, but their possible role in caries invasion is not understood. This study sought to examine the effects of immunoglobulin molecules on dentine permeability using a fluid-filtration method. Crown segments cut from impacted human third molars were treated by filtration with 100 micrograms/ml IgG, 100 micrograms/ml IgA or 30 micrograms/ml IgM under a constant pressure. Flow rates were recorded and percent changes in flow rate analysed over time. Filtrates collected at various times were tested for changes in immunoglobulin concentrations by an enzyme-linked immunosorbent assay, and the percent retention of immunoglobulins to dentine was calculated. There was a decreasing non-linear exponential relation between the percent changes in flow rate and filtration time for all three immunoglobulins. The percentage of retained immunoglobulins was significantly related to the filtration time for all three classes of immunoglobulins. Immunoglobulin retention contributed to significant changes in flow rate with time. These in vitro results indicate the potential mechanism of immunoglobulins in decreasing tabular permeability.

Dental Caries↗
PubMed2005

A study into dentists' knowledge of the treatment of traumatic injuries to young permanent incisors.

OBJECTIVE: The aims of this study were to evaluate dentists' knowledge of the emergency treatment of traumatic injuries to young permanent incisors, and to investigate barriers to treatment. DESIGN: A closed-ended questionnaire was sent to 1023 general dental practitioners (GDPs) and community dental officers (CDOs) in West/North Yorkshire and Humberside, UK. METHODS: The questionnaire comprised 17 questions. Six questions asked for general information about the participants (i.e. profession, age, gender, year of graduation, training or education on dental trauma, and willingness to provide emergency care), 10 were relevant to the emergency treatment of crown fractures, root fractures, luxation and avulsion injuries, and the last question queried any perceived barriers to treatment. Results. Seven hundred and twenty-four questionnaires were returned, a response rate of 71%, and these indicated that dentists' knowledge of the emergency treatment of dentoalveolar trauma in children was inadequate. The CDOs were significantly more knowledgeable than the GDPs, as were younger and more recently graduated dentists compared with older ones. The GDPs regarded the difficulty of treating children and the inadequate fees of the UK National Health Service as important barriers to treatment. Dentists who attended continuing dental education courses on dental traumatology had a more thorough knowledge than those who did not. CONCLUSION: Overall, the dentists' knowledge of the emergency treatment of dentoalveolar trauma in children was inadequate. Greater emphasis on undergraduate and postgraduate education in this area is indicated.

Adult↗
PubMed1996

The density and branching of dentinal tubules in human teeth.

Detailed knowledge of dentine structure, and especially that of the dentinal tubules, is essential in order to understand dentine permeability and to interpret data from investigations on dentine adhesive materials. The aim here was to examine the density and branching of dentinal tubules in human teeth by light and scanning electron microscopy. Stained and unstained demineralized sections and undemineralized fractured specimens were studied. Statistically significant differences in the density of tubules were found depending on location. Differences in density of tubules between the peripheral and inner aspects were more marked in the crown than in root. The mean number of dentinal tubules in the middle part of the root was significantly lower than in the middle part of the crown. The density of the tubules in the outer dentine at the cusp location was also significantly different from that subjacent to the occlusal fissure. The number of branches of dentinal tubules was particularly abundant in locations where the density of tubules was low. The branching patterns revealed an intricate and profuse canalicular, anastomosing system, criss-crossing the intertubular dentine. Three types of branches, major, fine and microbranches, were identified on the basis of size, direction and location. Major branches, 0.5-1.0 micron dia., were the typical delta branchings found peripherally. Fine branches, 300-700 nm dia., forked off at 45 degrees and were abundant in areas such as in the root where the density of the tubules was relatively low. Microbranches, 25-200 nm dia., extended at right angles from the tubules in all parts of the dentine. The findings emphasize the need for detailed characterization of dentine substrates for adhesive testing and of samples used in permeability studies.

Adolescent↗
PubMed1998

Complicated crown fracture of an unerupted permanent tooth--a case report.

Trauma to primary teeth may result in direct damage to underlying developing permanent teeth because of the close relationship that exists between the apices of the primary teeth and their permanent successors. Injuries to developing teeth have been classified into ten different categories, using a classification that is largely based on developmental alterations to the permanent teeth. However, this classification does not include other types of trauma that may occur to developing teeth, such as crown fractures. Although apparently rare, such injuries can occur by direct contact of the impacting object with a developing tooth, as illustrated by the following case report.

Child, Preschool↗
PubMed2001

Microhardness of enamel restored with fluoride and non-fluoride releasing dental materials.

Demineralization caused by frequent ion loss can be detected by a decrease in enamel microhardness. The purpose of this study was to determine the microhardness of the enamel adjacent to restorations with fluoride and non-fluoride dental materials after demineralization and remineralization treatments using crowns of 6 recently extracted unerupted third molars which were sectioned into 4 parts. Five penetrations were made in the enamel of the control group and in the enamel adjacent to restorations made with Vitremer, Heliomolar or Z100, to obtain the Knoop microhardness. There was no significant statistical difference between the microhardness of the enamel of the control group and the enamel adjacent to the restorations made with Vitremer and Heliomolar (p < 0.01), nor between the enamel adjacent to the Heliomolar and Z100 restorations. However, there was a statistically significant difference when the Z100 group was compared to the control group and to the Vitremer group. The results point out that some phenomena occurred which interferred with the ionic loss and, consequently, the microhardness of the enamel of the Vitremer and Heliomolar groups, because it was not possible to observe any difference between the microhardness of the enamel of the control group and the groups restored with Vitremer and Heliomolar.

Acrylic Resins↗
PubMed1995

Long-term survival of fragment bonding in the treatment of fractured crowns: a multicenter clinical study.

In three Scandinavian dental facilities, a series of 334 permanent incisors with fractures of the crown or crown and root was treated by reattachment of the fragment with a resin composite. Two centers (Oslo and Stockholm) employed acid etching of enamel alone for fragment bonding (n = 146), while the third center (Copenhagen) used a combination of enamel etching and dentinal bonding (n = 188). Although the final retention rate of fragment bonding was similar in the two groups, it took the dentinal bonding group almost three times as long to drop to 50% fragment retention. This difference could be attributed to greater bonding strength in the dentinal bonding group, greater risk of second injury in the younger acid-etching group, or difficulty in maintaining a dry operative field in the younger age group. The good fragment retention, acceptable esthetics, and pulpal vitality observed in the present series indicate that reattachment of the coronal fragment is a realistic alternative to placement of conventional resin-composite restorations.

Acid Etching, Dental↗
PubMed2005

Anatomic Endodontic Technology (AET)--a crown-down root canal preparation technique: basic concepts, operative procedure and instruments.

AIM: To illustrate the conceptual basis and the operative procedure of the Anatomic Endodontic Technology (AET) technique and to illustrate the specific instruments used in each phase. SUMMARY: The basic characteristics of the AET technique are reported. The instruments and procedure are described in three phases: coronal access, coronal-middle preparation and apical preparation. In the first phase, correct cavity design is described. In the coronal-middle phase, the use of four stainless steel shaping instruments, powered by a reciprocating handpiece is described, incorporating a brushing-milling action against canal walls. During the apical phase, dedicated apical stainless steel and NiTi hand instruments are used to complete the preparation. The stainless steel apical files are used with a 1/4 turn and withdrawal movement whilst the NiTi are used in 360 degrees rotary motion. KEY LEARNING POINTS: Most current canal shaping techniques do not prepare all the canal walls and can result in over-enlargement in some areas. AET defines three regions of the canal: coronal (from the cavo-surface of the access cavity), coronal-middle, and apical. Coronal-middle instrumentation is undertaken with four mechanically driven stainless steel shaping instrument used in brushing-milling action against canal walls. Apical preparation is completed by hand and with the formation of a stop.

Dental Alloys↗
PubMed2000

A new approach in maxillary molar distalization: intraoral bodily molar distalizer.

The objectives of our study were to achieve bodily molar distalization, avoid distal tipping of molars, eliminate the need for patient cooperation (no headgear, no elastics, and no esthetic and social concern), and finally to minimize the treatment period and maximize the treatment efficiency. The study was carried out on 5 males and 10 females, a total of 15 patients. Mean age for the study group was 13.53 years. Dentally, all the patients had Class II molar relationship on both sides. The patients were in permanent dentition, second molars were erupted, and the lower dental arch was well aligned. Patients showed normal or sagittally directed growth pattern. Lateral cephalograms and study models were taken and analyzed before and after molar distalization. In the present study, in order to achieve maxillary molar distalization, a new intraoral appliance was developed. The intraoral bodily molar distalizer (IBMB) was composed of 2 parts: the anchorage unit and the distalizing unit. The anchorage unit was a wide Nance button, and the active unit consisted of distalizing springs. The springs had 2 components: the distalizer section of the spring applied a crown tipping force, while the uprighting section of the spring applied a root uprighting force on the first molars. A total of 230 g of distalizing force was used on both sides. After the distal movement of the first molars, the cephalometric results of 15 patients showed the following. Maxillary first molars were moved distally by an average of 5.23 mm (P <.001) without tipping or extrusion. Maxillary first premolars were moved 4.33 mm mesially (P <.001), tipped 2.73 degrees distally (P <.05), and extruded by 3.33 mm (P <.001). Maxillary central incisors were proclined by an average of 4.7 mm (P <.001) and tipped 6.73 degrees labially (P <.01). Model analysis showed that maxillary first molars were not rotated, and intermolar distance did not change after distal movement of molars. In conclusion, unlike most of the other molar distalization mechanics, this newly developed device achieved (1) bodily distal movement of maxillary molars and (2) eliminated dependence on patient cooperation and did not require headgear wear for molar root uprighting.

Adolescent↗