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PubMed1998

Effect of tubule orientation in the cavity wall on the seal of dental filling materials: an in vitro study.

Dentinal tubules are oriented perpendicularly to the root canal walls but parallel to the lateral walls of class I occlusal preparation. It was hypothesized that the contact surface area of the material may depend on the tubule orientation in the cavity wall to which the material is applied, and that the difference in contact surface may affect the seal provided by the filling material. Standard central lumens, 2.6 mm in diameter and 3 mm high, were machined in human crown or root specimens. After removal of the smear layer with a conditioner, the specimens in each experimental group, consisting of 20 crown and 20 root specimens, were filled with amalgam, Fuji II glass ionomer (with or without varnish), or gutta-percha with Ketac-Endo root canal sealer. A modified fluid transport model was used to test the leakage along the fillings. Selected specimens were then split longitudinally and observed in a scanning electron microscope. The micrographs showed that all the test materials were pressed into the dentinal tubules. The contact surface of the material was calculated to be at least 45% larger in root specimens than in crown specimens, depending on the depth of the tubular penetration of the test material. The leakage results showed that all the test materials leaked less in root specimens than in crown specimens (P = 0.0000 for amalgam, P = 0.0374 for Fuji II with varnish, P = 0.0088 for Fuji II without varnish, P = 0.002 for gutta-percha with sealer). It was concluded that the tubule orientation in the cavity wall may influence the seal provided by certain dental filling materials.

Dental Alloys↗
PubMed1995

Crown and root resorption of a maxillary permanent first molar by an impacted second premolar: a case report.

A case is described of resorption of the mesial aspect of a maxillary permanent first molar in a 13-year-old boy whose maxillary second premolar was impacted. The premolar was partially erupted in the line of the arch and radiography revealed a radiolucent area involving enamel, dentine and cementum on the mesial aspect of the first molar. The first molar was extracted and the premolar erupted normally. The case emphasizes the importance of early diagnosis of developmental abnormalities.

Bicuspid↗
PubMed2001

Treatment of traumatized permanent incisors with crown and root fractures: a case report.

A case report of the treatment of permanent incisors with crown and root fractures is presented. A radiolucent lesion at the fracture lines was treated with calcium hydroxide in the coronal fragments for 18 months. Clinically, the teeth became firm and the radiographic results after 2 years showed healing of the lesion and hard tissue filling in the space at the fracture lines.

Calcification, Physiologic↗
PubMed2004

Combined technique with polyethylene fibers and composite resins in restoration of traumatized anterior teeth.

Traumatized anterior teeth need quick esthetic and functional repair. Esthetic requirements of anterior teeth require the use of composite materials which, in the most complex cases, can be used in association with fibers so as to improve their mechanical resistance. Many kinds of fibers are available. The authors considered parameters such as physical properties, water absorption, ease of cutting and of laying. Polyethylene fibers appear to have the best properties in elasticity, translucency, adaptability, tenaciousness, resistance to traction and to impact. Fifteen children, between 7 and 13 years old, with crown fractures of the anterior sector were treated. In the case of a simple crown fracture, the missing part was restored by polyethylene fibers and composite resins. In the case of a complex crown fracture needing endodontic treatment, the fibers were used as a central core stump in order to restore the dental morphology. At control examinations, the teeth restored by this technique were acceptable, both in function and in aesthetics. Thus, the authors recommend this combined technique for predictable restoration of traumatized anterior teeth.

Adolescent↗
PubMedDate not supplied

Dentinal dysplasia type I: review of the literature and report of a family.

A family is reported with dentinal dysplasia type I affecting both dentitions. Presenting features included unusual mobility of the teeth, followed by early exfoliation; normal clinical shape of the crowns of the teeth, but with an amber color without any sign of attrition or abnormal loss of enamel. Radiographic findings showed pulp-chamber and root-canal obliteration, poor root formation, radiolucent linear appearance of the pulp chamber parallel to the cementoenamel junction and frequent periapical radiolucencies. Histological studies have reported large masses of calcified tubular dentin, atypical osteodentin, and also true denticle.

Adult↗
PubMed2001

Periodontal status of mandibular incisors after pronounced orthodontic advancement during adolescence: a follow-up evaluation.

The purpose of this study was to analyze whether pronounced orthodontic advancement of the mandibular incisors during Class II correction in the mixed dentition results in gingival recession. Through mandibular superimposition of the pretreatment and posttreatment cephalograms of 67 Class II patients who were treated with reverse headgear to the mandibular dentition, 45 patients with a minimum of a 1-mm advancement of the cementoenamel junction (CEJ; mean, 2.18 +/- 0.87) and a minimum of a 2-mm advancement of the incisal edge (mean, 3.87 +/- 1.34) were identified. Using the same protocol in Class II patients, 30 individuals who finished treatment at a similar time and age, but without reverse headgear and with no advancement of the CEJ (mean -0.43, SD 0.53) and a maximum of 1-mm advancement of the incisal edge (mean -0.26, SD 1.15) were identified. Before treatment, the mandibular incisors were more retruded, relative to the line from point A to pogonion and relative to the mandibular plane in the patients with pronounced advancement than in those with no advancement of the mandibular incisors; no differences were found at the time of appliance removal. A total of 30 patients with pronounced advancement and 21 patients with no advancement could meet for a follow-up examination a mean period of 7.83 years (SD, 4.44) and 9.38 years (SD, 4.39) after treatment, respectively. Clinical examinations at the time of follow-up revealed no differences in the amount of recession, the width of attached gingiva, the length of supracrestal connective tissue attachment, the probing pocket depth, and gingival bleeding index or visible plaque index of the mandibular incisors between the patients in the 2 groups. An examination of color slides demonstrated no differences in the number of mandibular incisors that developed recession from before treatment to after treatment and from after treatment to follow-up. Measurement of mandibular incisor crown height on the study models demonstrated no difference in the increase in clinical crown height from after treatment to follow-up between the patients in the 2 groups. It was concluded that pronounced advancement of the mandibular incisors may be performed in adolescent patients with dentoalveolar retrusion without increasing the risk of recession.

Adolescent↗
PubMed1999

Ideal endodontic access in mandibular incisors.

Straight-line access in mandibular incisors facilitates locating and debridement of the canals. The purpose of this study was to plot where ideal access should be located in mandibular incisors to obtain straight-line access to the apical third of the root canal and to determine if a correlation exists between incisal edge wear and position of access opening. Two hundred and seventy-nine mandibular incisors were radiographed in clinical and proximal views. Straight-line access was determined by finding midpoints in the canal at two levels and extending a line connecting the points through the crown. Teeth were graded as to the condition of the incisal edge. Ideal straight-line access was determined to be at the incisal edge in 72.4% of the teeth, whereas in 27.6% of the teeth it was to the facial of the incisal edge. As the wear of the incisal edge increased, the ideal access moved from the facial toward the incisal.

Chi-Square Distribution↗
PubMed2001

Bracket positioning and resets: five steps to align crowns and roots consistently.

Orthodontists strive for accurate bracket positioning because it makes achieving a superior occlusion easier. Whether one uses a direct or an indirect bonding technique, the initial appliance placement typically includes some bracket-positioning errors. The clinician either corrects these errors during treatment or tediously repeats archwire bends to compensate for the misplaced brackets. The clinician should assess bracket positioning early in treatment by clinical and radiographic evaluations and then correct all positioning errors during a single dedicated reset appointment. This article describes a 5-step protocol for assessing and correcting bracket-positioning errors.

Humans↗
PubMedDate not supplied

The diagnostic value of coronal dark-gray discoloration in primary teeth following traumatic injuries.

The diagnostic value of dark-gray discoloration of the crown of primary incisors following traumatic injury as a predictor of pulp vitality is controversial. This retrospective study attempted to examine the condition of the pulp of primary incisors with dark-gray discoloration following traumatic injuries. Forty-eight gray caries-free, traumatized primary incisors were examined clinically and radiographically prior to treatment. All teeth included in the study were free of any clinical and/or radiographic signs of pulp necrosis. Crown discoloration was the only clinical or radiographic sign of pulp involvement. Pulpectomy was performed in five teeth within the first month after trauma, in 16 teeth during the second month, 11 teeth between 2 and 6 months, seven teeth between 6 and 12 months, and three teeth after more than a year. In six teeth the time of injury was unknown. Endodontic treatment was initiated without local anesthetic under rubber dam, access to the pulp chamber with high speed, and debridement with a barbed broach. Assessment of the pulp condition was made upon opening the pulp chamber, as follows: Vital-pulp bled when exposed; partial necrosis-bleeding disclosed at the apical area during debridement; total necrosis-no bleeding was observed. Pulp necrosis was found in 37 teeth (77.1%), 10 teeth (20.8%) presented partial necrosis, and only one tooth (2.1%) had a vital pulp. Dark-gray discoloration of primary incisors could be interpreted as an early sign of pulp degeneration that would deteriorate into necrosis. Moreover, discolored primary incisors can be necrotic even without presenting tenderness to percussion, increased mobility, and periapical osteitis.

Anesthesia, Local↗
PubMed2002

An in vitro L-band electron paramagnetic resonance study of highly irradiated whole teeth.

Regarding in vivo L-band dosimetry with human teeth, a number of preliminary experiments were carried out that were linked to the resonators response and the relative contribution of enamel to the EPR signal intensity of irradiated whole teeth. The sensitivity of the extended loop resonator varies in the antenna plane, but this variation tends to vanish when the sample is moved away from this plane. When the loop antenna is placed just above the highly irradiated molar, around 88% of the dosimetric signal is due to the crown enamel. The sensitivity inside a birdcage cavity is approximately equal over the volume of a molar; only 30% of the molar's total dosimetric signal results from enamel. Some decrease in the intensity of the dosimetric signal from enamel is observed after irradiation. At room temperature, the signal is reduced by about 20% within 90 days and approaches a plateau with a time constant of about 35 days.

Bicuspid↗
PubMed2002

Endodontic and periodontal treatments of a geminated mandibular first premolar.

AIM: To describe a rare case of gemination involving a mandibular first premolar. SUMMARY: The complex morphology of geminated teeth renders their endodontic and periodontal management difficult. Root canal and periodontal treatments were performed on a geminated mandibular first premolar with three canals. Clinical examination showed two separated crowns with united roots. Radiographically, two distinct pulp chambers with two joined and a third independent canal were seen. Conventional root canal treatment resulted in complete healing of the apical lesion. However, the occurrence of a vertical fracture led to the extraction of the mesial segment. At the follow-up visit, the distal segment was clinically healthy and continued to satisfy functional demands.

Adult↗
PubMed2003

Concentration of selected elements in the roots and crowns of both primary and permanent teeth with caries disease.

We examined the differences between the concentrations of chemical elements in caries-changed primary teeth and permanent ones with a division into the root and the crown. The study comprised 27 children aged from 4 to 11 yr and 36 adults aged from 36 to 71 yr. We examined the elements with the total reflection X-ray fluorescence method. The lowest concentrations of calcium, manganese, strontium, lead, and copper were in the roots of primary teeth compared to the roots of permanent ones. The calcium, nickel, zinc, lead, and copper concentrations were significantly higher in the roots of primary teeth than in the roots of permanent teeth. However, the zinc concentration was higher both in the root and crown of primary teeth than in permanent teeth. On the basis of our investigations, we can conclude that the content of some elements (manganese, copper, strontium, and lead) is higher in caries permanent teeth than in primary ones. The nickel and zinc concentrations are higher in the teeth of the children than the adults. However, the content of other elements (calcium, chromium, iron) is similar in both kinds of teeth.

Adult↗
PubMed2002

Density and diameter of dentinal tubules of first and second primary human molars--comparative scanning electron microscopy study.

The aim of the present survey was to evaluate tubule density and diameter of dentin of first and second primary human molars and compare the two dental categories. These evaluations were done solely at the middle third of the crowns of twenty extracted noncarious teeth separated in two groups (first molars and second molars). The tubule diameters observed were 0. 794 microm and 1.0 microm for first and second molars, respectively (measurements done at 35-65% from the pulp-chamber walls). Regarding tubular density, the measurements indicated 17,997.594 tubules/mm2 and 25,211.317 tubules/mm2 for first and second molars, respectively. Comparisons between-groups indicated that tubule diameter and density of dentin were higher in second molars, being the difference highly significant (P<0.01).

Child↗
PubMed2004

[Preservation of alveolar bone of un-restorable traumatized maxillary incisors for future].

UNLABELLED: Anterior maxillary implantation is a challenging treatment for both the surgeon and prosthodontist due to high esthetic demands in this area. However, it is the most traumatized and most exposed region to habits. Prompt and appropriate management can significantly improve prognosis of many dentoalveolar injuries, especially in young patients. Unfortunately, many traumatized teeth are overtreated or left untreated, which lead to a much more complicated treatment at the time of permanent restoration at adulthood. The facial cortical plate over the roots of the maxillary teeth is thin and porous. Periapical infections, as well as prolonged and stubborn surgical treatments (repeated root end surgeries) can cause resorption of the labial plate, migrate to a more palatal position, and may later require an augmentation procedure prior to implant placement. The treatment-options of traumatized, anterior maxillary, un-restorable fractured root and ankylosed infraocluded teeth, in relation to preservation of the adjacent alveolar bone for future use of dental implantation will be discussed. The recommended treatment of crown-root fracture of permanent incisor includes removal of the coronal fragment and supragingival restoration of the fractured root. In severe cases in which the fracture line positions deeply under the gingival margin, this treatment may be supplemented by gingivectomy and/or osteotomy, as well as surgical or orthodontic extrusion of the root. In young patients, use of these treatment options as temporary treatment to preserve the facial cortical plate is important. Preservation of alveolar dimension will enable implantation after the completion of growth and development. Dento-alveolar ankylosis accompanied by replacement resorption is a serious complication following severe injury to the periodontal membrane. This complication develops mainly following avulsion and intrusion but also following lateral luxation and root fracture. Replacement resorption develops after severe damage to the periodontal ligament cells that cover the root surface. As a result of this damage, the periodontal ligament is replaced by bone tissue, causing ankylosis between bone and tooth. Following ankylosis, resorption of cementum and root dentin occurs. These processes eventually result in replacement of the entire root by bone. In young children it could arrest the growth of the alveolar process and create an infra-occluded tooth, resulting in a severe bony defect that is difficult to correct. In addition, loss of the maxillary incisor leads to serious esthetic and restorative problems, particularly when the trauma occurs at a young age. Therefore, ankylosed teeth should be treated as soon as diagnosed. Alternative treatments include intentional extraction and immediate replantation of the ankylosed tooth to its socket after embedding the tooth and the socket in Emdogain. This treatment is indicated only when the ankylosis or the replacement resorption is diagnosed at an early stage or has affected only a small area of the root. When the resorption is diagnosed at a later stage, auto transplantation of first lower pre-molar to the anterior region or decoronation of the ankylosed tooth may be considered. Decoronation is a simple and safe surgical procedure for preservation of alveolar bone prior to implant placement. It should be considered as a treatment option for teeth affected by replacement resorption. The alternative treatment of surgical extraction of an ankylosed tooth often leads to considerable bone loss and reduced bone volume in the oro-facial dimension. This may later necessitate an augmentation procedure. CONCLUSION: Scrupulous diagnosis of teeth and the alveolar bone after a traumatic injury is necessary. Treatment is multidisciplinary, requiring endodontic, surgical, orthodontic, operative and prosthetic compliance. An individual treatment plan for each patient is necessary. General rule do not apply. Periodic check-up is essential.

Adult↗
PubMed2001

Three-dimensional inclination of the dental axes in healthy permanent dentitions--A cross-sectional study in a normal population.

The 3-dimensional (3-D) inclination of the facial axis of the clinical crown (FACC) and the size of the clinical crowns were measured in 100 white northern Italians. The subjects consisted of 22 girls and 21 boys, ages 13-15 years (adolescents), and 31 women and 26 men, ages 16-26 years (adults), all with a complete permanent dentition and Class I dental relationships. The 3-D coordinates of dental landmarks were obtained with a computerized electromagnetic digitizer. Clinical crowns heights and FACC inclinations in the anatomical frontal and sagittal planes relative to 2 reference planes, maxillary and mandibular (between the incisive papilla and the intersection of the palatal/lingual sulci of the first permanent molars with the gingival margin), were calculated. Ages and sexes were compared by ANOVA. On average, the frontal plane FACCs of most teeth converged toward the midline plane of symmetry. In contrast, the incisors diverged from the midline plane or were nearly vertical. Within each quadrant, the inclinations of the postincisor teeth progressively increased. In the sagittal plane, most teeth had a nearly vertical FACC. FACC inclinations showed sex- and age-related differences (P < .05). In the frontal plane, the canines, premolars, and molars were more inclined in adolescents than in adults. In the sagittal plane, a large within-group variability was observed. Clinical crown height was significantly larger in males than in females in all maxillary and mandibular canines, premolars, second molars, maxillary central incisors, and first molars. With age, some degree of dental eruption was found in maxillary and mandibular canines, maxillary second premolars, and molars. The age-related decrease in FACC inclination may be the effect of a progressive buccal and mesial drift.

Adolescent↗
PubMed2006

Radiographic features of the jaws and teeth in thalassaemia major.

OBJECTIVES: This investigation aimed to compare the radiographic changes and root and crown-body lengths of the mandibular first permanent molar in a group of thalassaemic patients with a control group, matched for age and sex. METHODS: Panoramic radiographs of 50 thalassaemic patients and 50 controls were examined for the presence of radiological changes. Crown body and root lengths were determined using the method of Seow and Lai. The average lengths were calculated and compared between the two groups. RESULTS: The mean crown-body and root lengths of the mandibular first molar of patients with thalassaemia major were 9.58+/-0.83 mm and 11.89+/-1.33 mm, while those for the control group were 10.45+/-0.78 mm and 12.78+/-1.67 mm, respectively. A significant difference (P<0.05) was found between the mean crown-body and root values of the two groups. A significant difference (P<0.05) was also found between thalassaemic patients and controls in the occurrence of spiky-shaped roots, root and crown lengths, taurodontism, attenuated lamina dura, enlarged bone marrow spaces, small maxillary sinuses, faint inferior alveolar canal and thin cortex of the mandible. CONCLUSIONS: While thalassaemia major may not be associated with the occurrence of either vascular canals or prominent antegonial notch, spiky-shaped and short roots, taurodonts, attenuated lamina dura, enlarged bone marrow spaces, small maxillary sinuses, absence of inferior alveolar canal and thin cortex of the mandible were found to be reliable diagnostic criteria for thalassaemia major.

Adolescent↗
PubMed1997

Attractive magnets for orthodontic extrusion of crown-root fractured teeth.

A subgingival crown-root fracture presents the clinician with a difficult restorative problem, including reaching the fracture line, and is complicated by the need to maintain the periodontal tissues in good health. The treatment options up to now have usually been limited to extrusion of the remaining root with a conventional orthodontic appliance, surgical intraalveolar transplantation of the root or extraction with bridge replacement. In this report, a new method of orthodontic extrusion with attractive magnets is presented. One or two neodymium-iron-boron magnets were attached to the remaining root and a second, larger neodymium-iron-boron magnet was incorporated in a removable appliance. The roots were extruded 2 to 3 mm with a force range from 50 to 240 cN during a treatment period of 9 to 11 weeks. Good force control at short distances, no friction, and no material fatigue of permanent rare earth magnets resulted in successful rapid extrusion. No evidence of soft tissue dehiscences, aberrant tooth mobility, or root resorption was found.

Adolescent↗
PubMed2006

Three-dimensional analysis of pulp chambers in maxillary second deciduous molars.

OBJECTIVE: The purpose of this study was to clarify the positional relationship between the crown contour and the pulp chamber using micro-CT system for restorations of maxillary second deciduous molar. METHODS: Five maxillary second deciduous molar teeth each from the deciduous dentition and the mixed dentition periods were used. The positional relationship between the crown contour and pulp chamber was three-dimensionally observed by micro-CT. In addition, the thickness of the dentin at each of the pulp horns and the volume ratio of the pulp chamber against the whole crown were measured. RESULTS: In relationship to the crown contour and the pulp chamber, the pulp horn of the mesiobuccal cusp showed greatest protrusion and eminent swelling of its mesial wall in both the deciduous dentition and the mixed dentition periods. Furthermore, the pulp chamber was shifted to the mesial side. The volume ratio of the pulp chamber to the whole crown, the ratio in the mixed dentition period showed to be significantly smaller than in the deciduous dentition period. The dentin thickness at the mesiobuccal pulp horn was the thinest. CONCLUSIONS: These results suggest that in preparation of cavities in maxillary second deciduous molars, care is necessary not to expose of the mesiobuccal pulp horn. Especially, the mesial wall of the mesiobuccal pulp horn should be noted.

Child↗