Dilaceration of a mandibular incisor: case report.
The various theories of tooth eruption are discussed and a dilacerated mandibular incisor which illustrates the diversity of potential for teeth to erupt, is reported.
Adolescent↗
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Developmental changes of mandibular permanent canines and premolars in early mixed dentition.
This study investigated the developmental changes of mandibular permanent canines and premolars in early mixed dentition using panoramic radiographs. Positions of cusps and root apices of the teeth relative to the inferior border of mandible were evaluated. The developmental stages of the teeth were divided into three stages. There were few changes in the inclination of the three teeth. The permanent canine began to erupt before stage 2 and the second premolar began to erupt after stage 2. The distance between the inferior border of the mandible and apices of the three teeth was almost fixed in early mixed dentition.
Alveolar Process↗
The erosive susceptibility of cervical versus occlusal enamel.
Clinical studies have strongly suggested a multifactorial aetiology for abfraction lesions or non-carious cervical tooth loss, with a contribution from erosive agents. Structural studies have shown that cervical enamel is more porous with a poorly developed crystal structure that may be more prone to erosion. The aim of this study was to examine the susceptibility to erosion of cervical and occlusal enamel from human premolar and molar teeth. Small blocks of cervical and cuspal enamel were immersed in either orange juice or Coca-Cola and the surface enamel loss was measured using profilometry. The enamel loss was essentially linear at a rate of 2.2-8.8 microns/hr. It was concluded that there was little difference in the susceptibility to erosion between cervical and cuspal enamel, even when the surface hypermineralised layer was removed.
Analysis of Variance↗
Atraumatic extraction and root retrieval using the periotome: a precursor to immediate placement of dental implants.
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Alveolar Process↗
Compomer materials and secondary caries formation.
PURPOSE: To evaluate the role of compomers in secondary caries formation in vitro. MATERIALS AND METHODS: 36 human teeth with caries-free enamel (coronal) and root surfaces underwent a fluoride-free prophylaxis. Class V cavities were prepared in buccal and lingual coronal and root surfaces. The teeth were divided into two groups with 3 treatment subdivisions [12 teeth per restorative material (6 with coronal restorations and 6 with root surface restorations)]). The preparations were restored with: (1) filled composite (Filtek Z250 with Single Bond), (2) fluoride-releasing compomer [Hytac with Prompt L-Pop (fluoride-releasing water-based adhesive)]; or (3) fluoride-releasing compomer [Dyract AP with Prime & Bond NT (fluoride-releasing acetone-based adhesive)]. 24 cavities (6 teeth with 2 cavities/tooth) were available with each treatment. The teeth were thermocycled (500 cycles at 5-50 degrees C) in synthetic saliva prior to artificial caries formation. After lesion formation, 5 longitudinal sections were taken from each specimen for polarized light evaluation. Mean surface lesion depths and wall lesion frequencies were determined. RESULTS: The Filtek Z250 group had significantly (P < 0.05, ANOVA, DMR) greater mean body of the lesion depths in coronal (205 microm) and root surfaces (221 microm) than either the Hytac (119 microm coronal and 161 microm root surfaces) or the Dyract AP (127 microm coronal and 149 microm root surfaces) groups. Likewise, wall lesion frequency was significantly higher (P < 0.05, ANOVA, DMR) for the Filtek Z250 group (41% coronal and 37% root surfaces) compared with either the Hytac (31% coronal and 25% root surfaces) or Dyract AP (26% coronal and 21% root surfaces) groups. No differences in outer body of the lesion depths or wall lesion frequencies were found between Hytac and Dyract AP for coronal and root surface restorations (P > 0.05, ANOVA, DMR).
Analysis of Variance↗
Fracture strength of fragment-bonded teeth. Effect of calcium hydroxide lining before bonding.
PURPOSE: To measure, in vitro the strength of intact teeth, fracture-bonded teeth, and fracture-bonded teeth bonded after a preliminary calcium hydroxide lining of the dentin part of the remaining tooth. MATERIALS AND METHODS: The study used 30 young, similarly aged sheep incisors. Twenty incisors were fractured 2.5 mm from the incisal edge and another 10 incisors remained non-fractured and served as control (Group 1). Group 2 comprised 10 fractured incisors, which after 3 weeks water storage were bonded by use of acid etching and a dentin bonding agent. In Group 3, the root part of 10 fractured incisors were lined with calcium hydroxide and kept in water for 3 weeks. Then the lining was removed with a hand instrument before bonding as above. The strength of the teeth in Groups 1-3 was measured and the mean fracture strengths representing the three groups were compared by Newman-Keuls' multiple range tests at a 5% level of significance. RESULTS: The mean fracture strength of the lined teeth (9.6 MPa) was significantly different from that of intact teeth (17.8 MPa) as well as from that of the bonded but unlined teeth (15.8 MPa). The latter two means were not significantly different. It is concluded that the use of calcium hydroxide on the fracture surfaces of fractured teeth before bonding lowers the fracture strength of the restored teeth.
Acid Etching, Dental↗
[The dynamics of pH, free calcium and total proteins in root plaque fluid and their relationships to the cariogenic potential].
OBJECTIVE: To enhance knowledge of root caries by analysis of the dynamics of dental plaque fluids on root surface and their relationships with the caries history. METHODS: The pH, free calcium and total proteins of dental plaque fluids on sound root surfaces were analyzed before and after the sucrose challenge. Subjects were either root caries-free (RCF) or caries-positive (RCP). RESULTS: After a sucrose challenge, the pH of plaque fluids dropped significantly and the concentration of free calcium increased significantly. There were no statistical differences in pH (RCF group 6.24 +/- 0.74, RCP group 5.96 +/- 0.70) and free calcium [RCF group (0.60 +/- 0.46) mmol/L, RCP group (0.89 +/- 0.54) mmol/L] between RCF and RCP group before sucrose challenge. Following sucrose exposure, pH (5.14 +/- 0.19) and free calcium [(1.73 +/- 0.74) mmol/L] in RCP group were significantly lower than RCP group [(pH 5.28 +/- 0.16), free calcium (2.73 +/- 1.25) mmol/L]. No interrelationship has been found between the amount of total proteins and free calcium. Components (contents, change trend) in root plaque were strongly related to that in coronal plaque. CONCLUSIONS: The process of root caries may be consistent to coronal caries regarding to the acid production of bacteria after a sucrose challenge. Plaque compositions show a stronger cariogenic potential in RCP group.
Calcium↗
Dental management of traumatic injuries to the primary dentition.
There is considerable information on traumatic injury management of permanent teeth. However, there are no conclusive guidelines for treating traumatized primary teeth. This article will summarize a number of issues relative to primary dentition trauma and provide a system for treatment.
Age Factors↗
Incidence of oral tissue trauma after the administration of general anesthesia.
BACKGROUND: Administration of general anesthesia necessitates certain amounts of manipulation or instrumentation within the mouth that may cause some oral tissue injuries. The purpose of this study was to determine the incidence of oral tissue trauma after receiving general anesthesia. Some possible risk factors were explored. METHODS: Four hundred and four adult patients receiving surgical procedures under general anesthesia facilitated by endotracheal intubation were included in this prospective survey. In each patient detailed oral and dental conditions were evaluated and recorded by an oral surgeon before and after operation. The extent of oral tissue trauma were computed and the type and character of the injury were recorded. RESULTS: Twenty-eight patients (6.9%) were found to sustain various degrees of oral trauma that included soft tissue laceration, tooth fracture, prosthesis damage, tooth avulsion, ecchymosis and numbness of tongue. Preexistence of missing tooth, crown, and residual root were some possible risk factors that might predispose to complication. CONCLUSIONS: Oral tissue trauma as it seems to be a common anesthetic complication that should be considered as a recognized hazard of general anesthesia. Understanding and recognizing oral anatomical condition and pathological change before anesthesia may help the anesthesiologists in preventing oral and dental complications and thus to avoid legal suits.
Adolescent↗
[3-dimensional cephalometry in orthodontics. The current possibilities of Cepha 3DT software].
A 3D cephalometric analysis method from a scanner acquisition, has been developed thanks to a long collaboration between the CIRAD modeling Laboratory and Jacques Treil. The model of skeletal description is based on eight landmarks related to the neuromatrical axis of facial growth (heads of the mallei, supraorbital, suborbital, submental points); it has been abundantly described. The purpose of this work consists in presenting the dentoalveolar level of the analysis. The description and the marking of the arches and the teeth mainly rest on the systematic use of a mathematical tool, the calculation of the central matrix of inertia, and on three fundamental choices: the identification of the dental arches from their constituting teeth leaving aside any alveolar marking, the marking of each tooth relative to the arch, as it can be observed by the orthodontist's eye, and not relative to the craniofacial architecture, the definition of the position of each tooth by the orientation of its coronoradicular axis and not its sole buccal side, Their uses in orthodontics are numerous: diagnosis, choice of the mechanics, therapeutic simulation, therapeutic follow up, analysis of the findings... Clinical applications illustrate the theoretical presentation.
Cephalometry↗
Oral self-mutilation in the Lesch-Nyhan syndrome.
Lesch-Nyhan Syndrome is a disorder caused by congenital absence of a purine metabolic enzyme, hypoxanthine-guanine phosphoribosyl transferase (HPRT). This syndrome is characterized clinically by mental retardation, chorea, athetosis, hyperuricemia, uricosuria and self-mutilation. This report is of two children, who are cousins, both of whom have Lesch-Nyhan syndrome and presented with severe self-mutilation wounds on their lip(s). Vital pulpotomy and coronal resection was done as a more conservative approach than extracting all offending teeth. By maintaining the root portion of the teeth in the bone, it is expected that preservation of the alveolar bone will be achieved.
Bicuspid↗
A case report of an intracoronal radiolucency in an unerupted permanent tooth.
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Bicuspid↗
Use of fluoride-containing sealant on proximal surfaces.
A visible light curing sealant was developed for the prevention of caries on the smooth surfaces especially on the proximal surfaces. The sealant is mainly composed of dimethacrylate monomers. It contains a total amount of 2.28 mass% fluoride as poly(methyl methacrylate-co-methacryloyl fluoride) and sodium fluoride. The fluoride-containing sealant could be successfully applied to the proximal surfaces between the first and second primary molars by making access to the interproximal space with an orthodontic separating module. Availability of fluoride was assessed by the concentration of fluoride released into 1 ml of distilled water as a function of time from disks 5 mm in diameter and 0.2 mm in thickness. Ten microg of fluoride was measured on the first day; after 3 days the rate remained fairly constant at about 1 pg/day for a period of 28 days. The fluoride uptake and the improved acid solubility were investigated in vitro using bovine incisors. The fluoride of the control, that is enamel without sealant treatment, was not detectable. The fluoride incorporated into enamel after 37 hours application was 2,100 ppm at 2 pm from the enamel surface. The enamel solubility to acids decreased by the fluoride incorporation.
Animals↗
The influence of a packable resin composite, conventional resin composite and amalgam on molar cuspal stiffness.
Packable resin composites may offer improved properties and clinical performance over conventional resin composites or dental amalgam. This in vitro study examined the cuspal stiffness of molars restored with a packable resin composite, a conventional posterior microfilled resin composite and amalgam. Forty-eight intact caries-free human third molars were distributed into four treatment groups (n=12) so that the mean cross-sectional areas of all groups were equal. Standardized MOD cavity preparations were made and specimens restored using one of four restorative materials: (1) a spherical particle amalgam (Tytin); (2) Tytin amalgam with a dentin adhesive liner (OptiBond Solo); (3) a conventional microfilled posterior resin composite (Heliomolar); (4) a packable posterior resin composite (Prodigy Posterior). Cuspal stiffness was measured using a Bionix 200 biomaterials testing machine (MTS). Specimens were loaded vertically to 300 N at a crosshead speed of 1.0 mm/minute. Stiffness was measured at 10 intervals: (1) prior to cavity preparation (intact); (2) following cavity preparation, but before restoration; (3) seven days after restoration; then (4) 1, 2, 3, 4, 5, 6 and 12 months after restoration. All specimens were stored at 37 degrees C in deionized water throughout the study and thermocycled (5 degrees/55 degrees C; 2000 cycles) monthly for 12 months. Repeated Measures ANOVA revealed significant differences among treatment groups over time (p<0.0001). Cavity preparation reduced cuspal stiffness by more than 60%. At 12 months, the cuspal stiffness of restored teeth was, on average, 58% that of intact specimens. Neither the packable nor the conventional resin composite increased cuspal stiffness over that of amalgam.
Acrylic Resins↗
The use of resin-based composite in children.
Resin-based composites are an integral component of contemporary pediatric restorative dentistry. They can be utilized effectively for preventive resin restorations, moderate Class II restorations, Class III restorations, Class IV restorations, Class V restorations and strip crowns. Tooth isolation to prevent contamination is a critical factor, and high-risk children may not be ideal candidates for resin-based composite restorations. Important factors to consider during composite placement are isolation, polymerization shrinkage and extent of restoration. When utilized correctly, resin-based composites can provide excellent restorations in the primary and permanent dentition.
Child↗
A survey of cusp fractures in a population of general dental practices.
PURPOSE: This study was conducted to expand the knowledge on the incidence of complete cusp fractures of posterior teeth in Dutch general practices. MATERIALS AND METHODS: During a 3-month period, data were obtained from 28 general practitioners, representing 46,394 patients. For each new case of complete cusp fracture, clinicians recorded information using a standard form with questions relating to location of the fracture, cause of fracture, and restorative status of the tooth prior to the cusp fracture. RESULTS: There were 238 cases of complete cusp fracture recorded. The results of this study indicate an incidence rate of cusp fractures of 20.5 per 1,000 person-years at risk. Molars were more frequently registered with cusp fractures than premolars (79% vs 21%). Maxillary molars presented more fractures of buccal cusps (66% vs 34%), while mandibular molars presented more fractures of lingual cusps (75% vs 25%). Almost 77% of the cases had been restored on three or more surfaces. Statistical analysis revealed a positive correlation between history of endodontic treatment and subgingival fracture location. Mastication was most frequently reported as the cause for fracture (54%), although one can argue whether the occlusal force was the cause or the immediate reason. CONCLUSION: This study revealed that complete cusp fracture is a common phenomenon in dental practice and has shown differences in cusp fracture with respect to tooth type and restorative status of the tooth. Teeth with a history of endodontic treatment are susceptible to unfavorable subgingival fracture locations.
Adult↗
Tooth fragment reattachment: fundamentals of the technique and two case reports.
Coronal fractures must be approached in a methodical and clinically indicated way to achieve successful restoration. One option for treatment is reattachment of the dental fragment. Reattachment creates a very positive emotional response in the patient and simplifies the maintenance of the patient's original occlusion. This article discusses dental fragment reattachment techniques and presents clinical cases of coronal fracture involving enamel, dentin, and pulpal exposure.
Adolescent↗
[Choice of size of anterior teeth in black African patients].
The choice of the size of artificial teeth takes an important place in the treatment of edentulism with removable prosthesis. However, the standards or proportions commonly used as guide have been developed mainly on Caucasian populations. This study have been undertaken to determine some proportions between anterior upper teeth and some maxillo-facial structures in black African subjects. The results suggest that the proportions generally used to choice the anterior upper artificial teeth in Caucasian subjects can not been applied in melanoderme African patients.
Adolescent↗