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PubMed1997

[The effect of root canal irrigation and variance of apical foramen pressure by use of casing aspiration needle system in vitro].

The authors introduced casing aspiration needle system (CANS) to irrigating root canal. The effect of root irrigation on removing canal debris and the variance of apical foramen pressure on extracted teeth were compared between the conventional irrigation and CANS irrigation. The results indicated that the effect of root canal irrigation by CANS was much better than the conventional method (P < 0.01). CANS irrigation didn't produce pressure to apical foramen during root canal irrigation. However, in the conventional method, with irrigation needle inserted deeper and deeper in root cancal the pressure of apical foramen gets higher and higher.

Humans↗
PubMed2003

Management of the immature apex--a clinical guide.

The production of an apical barrier prior to the placement of a permanent gutta percha root filling in a non-vital immature incisor tooth with an open apex is a well researched and documented technique. The technique is successful and a very satisfactory root filling can be placed in the tooth. However, dentists seem to have difficulty in achieving satisfactory outcomes.

Calcium Hydroxide↗
PubMed1998

Morphometrical analysis of main and accessory canals in apical root portion of frontal teeth.

Reviewing radiographs may often lead to a wrong conclusion regarding root canal ending (apical constriction) and anatomical apex of the tooth root. Anthropological measurements may help clinicians to understand better root canal ending aberrations in a sense to decide whether to do a revision of the root canal filling or not. The object of this investigation was to examine the deviation frequency, the distance of the major apical foramen from the anatomical apex and occurrence and number of accessory canals in the apical third of the frontal teeth roots. A total of 156 randomly chosen upper and lower permanent incisors and canines, after extraction due to periodontal disease were prepared for the investigation. The access cavity was prepared and root canal therapy was initiated just to prepare endodontic space for methylene blue dye injection. Methylene blue clearly dyed all root canal exits and after that the teeth were cut and examined with a stereomicroscope and a sliding scale. Results indicate that deviation frequency was found in 60.25% of the cases and the mean distance between deviated major foramen and the anatomical root apex was 0.35 mm. Accessory canals were found in 33.33% of the cases in the apex third of the root. Data were statistically elaborated with the method of Chi-square test.

Dental Pulp Cavity↗
PubMed1983

Sympathetic innervation at the apex of the cat's canine tooth - a quantitative analysis.

Superior cervical ganglia were removed unilaterally from 6 adult cats. 2 animals were sacrificed at 2, 4 and 7 d and the innervation of the canine apex examined quantitatively. The number of non-myelinated axons was lower on the operated side 4 and 7 d after sympathectomy. The number of degenerating axons was always greatest on the operated side and highest 2 d after operation. By combining the proportion of axons lost with those in the process of degenerating it is estimated that between 4.8 and 12.5% of the axons (52-88 axons) entering the apex of the cat's canine are sympathetic. Degenerating axons were often within the same Schwann cell as intact, presumably sensory, axons and were sometimes in contact with them. This contact may be the anatomical basis for the modulation of nociceptive input by sympathetic activity.

Animals↗
PubMed1998

Scanning electron microscopy and histologic analysis of an apexification "cap": a case report.

A maxillary permanent central incisor with a history of trauma, apexification, and internal thermocatalytic bleaching sustained a horizontal fracture at the cementoenamel junction, which necessitated extraction of the tooth. After removal, the root apex was examined histologically and by scanning electron microscopy. An apexification "cap" with unusual anatomic character and structure was observed.

Adult↗
PubMed2003

The accuracy of three methods of age estimation using radiographic measurements of developing teeth.

The accuracy of age estimation using three quantitative methods of developing permanent teeth was investigated. These were Mörnstad et al. [Scand. J. Dent. Res. 102 (1994) 137], Liversidge and Molleson [J. For. Sci. 44 (1999) 917] and Carels et al. [J. Biol. Bucc. 19 (1991) 297]. The sample consisted of 145 white Caucasian children (75 girls, 70 boys) aged between 8 and 13 years. Tooth length and apex width of mandibular canine, premolars and first and second molars were measured from orthopantomographs using a digitiser. These data were substituted into equations from the three methods and estimated age was calculated and compared to chronological age. Age was under-estimated in boys and girls using all the three methods; the mean difference between chronological and estimated ages for method I was -0.83 (standard deviation +/-0.96) years for boys and -0.67 (+/-0.76) years for girls; method II -0.79 (+/-0.93) and -0.63 (+/-0.92); method III -1.03 (+/-1.48) and -1.35 (+/-1.11) for boys and girls, respectively. Further analysis of age cohorts, found the most accurate method to be method I for the age group 8.00-8.99 years where age could be predicted to 0.14+/-0.44 years (boys) and 0.10+/-0.32 years (girls). Accuracy was greater for younger children compared to older children and this decreased with age.

Adolescent↗
PubMed1997

The treatment of nonvital immature teeth with calcium hydroxide-sterile water paste: two case reports.

Death of the dental pulp before completion of root development results in a tooth with an open apex. During endodontic treatment, the open apex makes obturation difficult, because there is no apical stop against which the filling can be packed and condensed. For many years, open apices have been treated by root canal fillings or by periapical surgery with or without a reverse seal. Currently, the conservative approach is preferred over surgical management, to avoid the physical and psychological trauma of surgery to a young patient. Two patients were treated by calcium hydroxide-sterile water paste to promote the apexification of the nonvital teeth with an incompletely formed apex. Normal endodontic preparation of the canal had been carried out in the immature tooth. Radiologic examination after 6 to 9 months showed that the apex of the maxillary incisors was completed by newly formed tissue.

Calcium Compounds↗
PubMed1989

Distribution of mesencephalic nucleus and trigeminal ganglion mechanoreceptors in the periodontal ligament of the cat.

1. In anaesthetized cats recordings have been made in the mesencephalic nucleus of the fifth cranial nerve and the trigeminal ganglion from neurones that respond when forces are applied to the mandibular canine tooth. The site of the mechanoreceptors in the periodontal ligament and their distribution around the tooth root have been determined. 2. Receptors with their cell bodies in the mesencephalic nucleus were found to be situated in the periodontal ligament in a discrete area intermediate between the fulcrum and apex of the tooth, while those in the trigeminal ganglion were situated in the whole area of the periodontal ligament between the fulcrum and apex of the tooth. 3. All of the located mechanoreceptors responded maximally when that part of the ligament in which they lay was put under tension. 4. The directional sensitivities of the mechanoreceptors suggested that there was an uneven distribution around the tooth root of receptors with cell bodies in the mesencephalic nucleus. In contrast mechanoreceptors with cell bodies in the trigeminal ganglion were distributed more equally around the tooth root. The rationale for the differences requires further investigation.

Action Potentials↗
PubMed2003

The use and predictable placement of Mineral Trioxide Aggregate in one-visit apexification cases.

Endodontic treatment of the pulpless tooth with an immature root apex poses a special challenge for the clinician. The main difficulty encountered is the lack of an apical stop against which to compact an interim dressing of calcium hydroxide (Ca(OH)2), or the final obturation material. In these situations the unpredictability of the result, the difficulty in creating a leak-proof temporary restoration for the duration of treatment, and the difficulty in protecting the thin root from fracture may lead to complications when using traditional (Ca(OH)2-based) apexification techniques. Furthermore, given the increased mobility of today's society, lengthy treatment protocols are fraught with problems, and may not be followed through to completion. This may lead to ultimate failure of the case. Mineral Trioxide Aggregate (MTA) has recently been introduced for use in endodontics. Current literature supports its efficacy in a multitude of procedures including apexification. The focus of this paper is to propose a one-visit apexification protocol with MTA as an alternative to the traditional treatment practices with Ca(OH)2. One-visit apexification may shorten the treatment time between the patient's first appointment and the final restoration. The importance of this approach lies in the expedient cleaning and shaping of the root canal system, followed by its apical seal with a material that favours regeneration. Furthermore, the potential for fractures of immature teeth with thin roots is reduced, as a bonded core can be placed immediately within the root canal.

Aluminum Compounds↗
PubMed1996

Regional bond strengths of resins to human root dentine.

OBJECTIVES: The demand for restoration of root dentine defects such as cervical erosion and root caries has significantly increased recently, but there is limited information on the performance of the adhesive resins to radicular dentine. The purpose of this study was to measure the regional tensile bond strength (TBS) of composite bonded to human root and coronal dentine, and to observe the interface between resin and root dentine by SEM. METHODS: Human extracted cuspid teeth were used to measure TBS with a new microtensile bond test. Enamel and cementum were removed from the labial tooth surfaces to form a long cavity preparation into dentine from the mid-crown to the apex of the root within the same tooth. All Bond 2 (all etch technique) or Imperva Bond (no etch) was bonded to dentine surfaces and covered with Protect Liner resin composite. The resin-bonded teeth were serially sliced into 16 sections at right angles to the long axis of the tooth, and the bonded surfaces were trimmed to give a bonded surface area of 1 mm2 for TBS testing. RESULTS: All Bond 2 bond strengths to coronal and apical dentine showed high values (23.5 MPa) but the bond strength was significantly lower on cervical root dentine. Imperva Bond produced a relatively high tensile bond strength to all regional areas. SEM showed that the thickness of the resin-infiltrated layer formed by All Bond 2 in root dentine was less than coronal areas. Resin infiltration with Imperva Bond was always less than 0.5 micron. The results suggest that high TBS values can be obtained with minimal resin infiltration in root dentine.

Acid Etching, Dental↗
PubMed1989

A longitudinal study of changes in frequency and technical standard of endodontic treatment in a Swedish population.

Longitudinal studies of endodontic treatment are rare. The purpose of this investigation was to study changes in frequency, technical standard and treatment need in a Swedish population with an interval of 5-7 years. The number of endodontically treated teeth in the population increased while the number of periradicular radiolucencies was at about the same level at the second examination. The number of radiolucencies found in endodontically treated teeth was reduced while it was increased in untreated teeth. The number of root fillings ending less than or equal to 2 mm from the apex of the tooth as well as fillings with a proper seal had increased at the second examination, but still only 40.2% ended less than or equal to 2 mm from the apex of the tooth and 59.1% of the root fillings were judged to have a proper seal. It was concluded that a great need for endodontic treatment existed in the population examined. A slight improvement in the quality of the treatment was evident at the second examination. However, the technical standard was still poor and obviously affected the outcome of the treatment. It is the opinion of the authors that endodontic treatment methods should be simplified as much as possible in an effort to improve the technical quality of the treatment. The prognosis of endodontic treatment would then improve as well.

Adult↗
PubMed1998

Regional bond strengths of self-etching/self-priming adhesive systems.

The purpose of this study was to measure the regional tensile bond strengths (TBS) at various portions of human tooth enamel and dentin, and to observe the resin-dentin interfaces of two commercially available self-etching/self-priming adhesive systems by scanning electron microscopy (SEM). Twelve extracted human cuspid teeth were used to measure TBS and four additional teeth were used for scanning electron microscopy (SEM). Outer enamel and dentin were removed from the labial tooth surfaces to form a long cavity preparation into middle dentin extending from the mid-crown to the apex of the root within the same tooth. Either Clearfil Liner Bond 2 (LB 2, Kuraray) or Fluoro Bond (FB, Shofu) was bonded to the surfaces, and covered with resin-composite. The resin-bonded teeth were serially sliced at right angles to the long axis of the tooth, and the bonded surfaces were trimmed to give a bonded cross-sectional surface area of 1 mm2 for TBS tests. LB 2 and FB showed significantly higher TBS in coronal, cervical and middle root dentin than that in enamel and apical root dentin. SEM showed that the thickness of the hybrid layer of both systems was about 1.0 microm in coronal, cervical and middle root dentin, and less than 0.5 microm in apical root dentin. These results suggested that the self-etching/self-priming systems produce good adhesion in coronal, cervical and middle root dentin by creating thin hybrid and transitional layers, but bonding to enamel and apical root dentin should be improved.

Acid Etching, Dental↗
PubMed2006

Radiographic assessment of post-retained crowns in an adult Jordanian population.

AIM: The objective of this study was to radiographically assess and compare the quality of post-retained crowns fabricated at the Dental Health Centre of the Jordan University of Science & Technology (JUST). METHODS AND MATERIALS: Study data were collected in 2002 from existing dental records for all patients receiving treatment with post-retained crowns between October, 1997 and June, 1999. The posts were assessed radiographically to evaluate various aspects of the quality of post-retained crowns. All 129 posts were fabricated in the dental school. RESULTS: The most-frequently restored teeth were the maxillary incisors (38.8%). Sixty-two percent of the posts were tapered, while 38% were parallel-sided. The mean length of the posts was 0.95 mm (SD 0.41) with a range between 0.22-2.85 mm. Caries was diagnosed radiographically in 10.8% of cases with lesions located on root surfaces in 64.3% of them, while 35.7% of lesions were within the root canal. Three posts (2.3%) were deviated from the line of the root canal in the mesio-distal plane. No evidence of root filling was found in 2.3% of the cases. In the remainder of teeth 15.5% had gutta percha extended to the radiographic apex of the tooth, while 59.7% fell 0.5-1 mm short of the radiographic apex. Gutta-percha was extruded beyond the apex in 22.5% of the teeth. Space between the end of the post and the root filling was found in 22.2%. The percentage of canals with apparently completely healthy periapical tissue was 51.2%. In the rest of the cases 34.8% had areas of radiolucency at or near the root apices and 14% demonstrated widening of the periodontal space around the root apex. Root resection had been completed in 2.3% cases. Signs of external resorption were apparent in one case (0.78%). CONCLUSION: The standards of the treatment of the endodontically treated teeth made at the dental hospital were satisfactory but could be improved by a controlled academic supervisory environment and a strict scientific approach to fixed prosthodontics within the dental school.

Adult↗
PubMed1986

Splinting and replantation after traumatic avulsion.

A rational approach can be taken in the dental office to avulsion and replantation. Consideration must be given to: Extraoral time. During this critical time, the prognosis for successful replantation noticeably decreases as the out-of-mouth time increases. Transport. Preferably the tooth will be transported in the socket, but milk or water may be used to keep the tooth moist. The buccal vestibule may be recommended for adults and teenagers but not for young children. Root surface. The root surface must not be handled, scraped, brushed, or have any part removed; it can be rinsed with sterile water, saline, or tap water but not with caustic solutions, disinfectants, or medicaments to clean the surface. Endodontic treatment. A tooth with an open apex should be evaluated bimonthly for revitalization. A tooth with a fully formed apex should have the pulp removed in 7 to 14 days after avulsion. Status of the alveolar process. Alveolar fractures may require a modified splint design to provide additional strength for a longer splinting duration. Obturation materials. Calcium hydroxide paste is used for a minimum of 6 to 24 months before filling permanently with gutta-percha. Selection of a splint. Each case is different and should be treated as such. Special consideration must be given to splint design, which will directly influence the desired result. Although any number of splints may be effective, inherent advantages and disadvantages of each should be understood fully by the clinician. This is where the art, the clinical experience, and the common sense of endodontic therapy dictate the proper splint and appropriate duration of splinting for the patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1999

Age-related morphometry of equine incisors.

In the present study the age-related morphological characteristics of 948 equine incisors were investigated. After extraction, total incisival length and root length were measured at the vestibular side of the teeth. Equine incisors reach their maximal length 2-3 years after eruption. Notwithstanding severe occlusal wear, this maximal length is maintained during most of the horses' life due to prolonged root formation. Root formation, at the rate of 2.5 mm per year, starts at the age of 5-6 years and continues until the age of 17. As the root of the incisor develops, its apical foramen narrows and changes position. In young horses the apical foramen is situated at the apex of the tooth, whereas in older individuals it is located at the mesial, distal, or lingual side of the tooth at a distance of 5-15 mm from the dental apex. In horses aged over 20 years apical foramina are still present. Radiographic imaging is a good method with which to obtain reliable information concerning the total incisival length and the size and position of the apical foramen.

Aging↗
PubMedDate not supplied

The effect of base/liner use on restoration leakage.

Central to the success of a restoration is the quality of the restoration-dentin interfacial seal; any compromise of the seal can lead to secondary or recurrent decay. Class V restorations have a high leakage propensity and this study evaluates the effect of base/liner placement on leakage behavior. Class V intracoronal half enamel/half dentin preparations (3.0 x 2.0 x 2.0 mm) were cut in four groups (n = 10) of extracted human teeth with a new bur used for each cavity preparation. All teeth were single-rooted, single-canal anterior teeth. Base/liner usage differed between each group. The first group of teeth had no liner or base, while a liner was placed in the second group of teeth prior to conditioning and restoration. A base was placed in the third group of cavity preparations and both the base and liner were placed in the fourth group. After preparation, a small diameter bare-end PVC-insulated copper wire was inserted within the root canal of each tooth from the apex to firm contact with the pulp chamber roof. The tooth-wire interface and root surface was sealed and leakage was followed electrochemically for 35 days in 0.9% NaCl solution. All of the teeth leaked to some degree; however, teeth that were restored without liner or base demonstrated the smallest amount of leakage. The greatest leakage was noted in teeth restored with both a base and a liner; teeth restored with only a base showed greater leakage than those restored with only a liner. The findings indicate that the presence of a base and/or a liner results in greater leakage compared with intracoronal Class V preparations that were conditioned and restored only. The data suggest that placing both a base and a liner increases restoration leakage significantly.

Acid Etching, Dental↗
PubMed1977

Measurement of edgewise torque force in vitro.

The construction of a model for the measurement of palatal root torque is described. It was demonstrated that: 1. Halfway between the apex of a tooth and the arch wire the force was double that which was delivered at the apex. 2. The lateral incisors were subjected to appreciably more force than the central incisors. 3. The smaller the number of teeth acted upon, the greater the force they received.

Humans↗