PURPOSE: The aim of this study was to define a color space of non-vital teeth and to compare it with the color space of matched vital teeth, recorded in the same patients. MATERIALS AND METHODS: In a group of 218 patients, with the age range from 17 to 70, the middle third of the buccal surface of 359 devitalized teeth was measured using a clinical spectrophotometer (Vita Easyshade Advance). Lightness (L*), chromatic parameters (a*, b*), chroma (C*), hue angle (h) and the closest Vita shade in Classical and 3D Master codifications were recorded. For each patient, the same data were recorded in a vital reference tooth. The measurements were performed by the same operator with the same spectrophotometer, using a standardized protocol for color evaluation. RESULTS: The color coordinates of non-vital teeth varied as follows: lightness L*: 52.83–92.93, C*: 8.23–58.90, h: 51.20–101.53, a*: −2.53–24.80, b*: 8.10–53.43. For the reference vital teeth, the ranges of color parameters were: L*: 60.90–97.16, C*: 8.43–39.23, h: 75.30–101.13, a*: −2.36–9.60, b*: 8.36–39.23. The color differences between vital and non-vital teeth depended on tooth group, but not on patient age. CONCLUSION: Non-vital teeth had a wider color space than vital ones. Non-vital teeth were darker (decreased lightness), more saturated (increased chroma), and with an increased range of the hue interval. An increased tendency towards positive values on the a* and b* axes suggested redder and yellower non-vital teeth compared to vital ones.
Humans ; Tooth ; Tooth, Nonvital

PURPOSE: The purpose of present study was to investigate fracture strength and mode of failure of endodontically treated teeth restored with metal cast post-core system, prefabricated fiber post system, and newly introduced polyetherketoneketone (PEKK) post-core system. MATERIALS AND METHODS: A total of 21 mandibular premolar were randomly grouped into 3 groups of 7 each according to the post material. Group A was for metal cast post core; Group B for prefabricated glass fiber post and resin core; and Group C for milled PEKK post cores. All specimens were restored with metal crown. The fracture strength of each specimen was measured by applying a static load of 135-degree to the tooth at 2 mm/min crosshead speed using a universal testing machine. After the fracture strength measurement, the mode of failure was observed. The results were analyzed using Kruscal-Wallis test and post hoc Mann-Whitney U test at confidence interval α = .05. RESULTS: Fracture resistance of PEKK post core was lower than those of cast metal post and fiber reinforced post with composite resin core. In the aspect of fracture mode most of the root fracture occurred in the metal post core, whereas the post detachment occurred mainly in the fiber reinforced post. In the case of PEKK post core, teeth and post were fractured together. CONCLUSION: It is necessary to select appropriate materials of post for extensively damaged teeth restoration and clinical application of the PEKK post seems to require more research on improvement of strength.
Bicuspid ; Crowns ; Glass ; Tooth ; Tooth, Nonvital

The management of teeth in the line of a mandibular fracture is controversial despite the general agreement that most of these teeth can be preserved. Teeth should be retained if bony attachments are adequate for survival, the tooth is sound and important in maintaining fixation of the fractured segment of bone. Teeth should be removed if they are loose and interfere with the reduction of fragments, are devitalized and potentially a source of wound infection, are damaged beyond their usefulness or may become devital and interfere with healing by becoming infected. However, tooth removal will increase the level of trauma, extend the severity of the wound and require expensive prosthetic treatment. Therefore, it is very important to conserve infected teeth in the line of a mandibular fracture through early primary endodontic treatment (pulp extirpation, canal enlargement and canal opening drainage) and splinting. The basic principles underlying the treatment of pulpless teeth are those underlying general surgery. Therefore, debridement of the infected wound (pulp extirpation and canal enlargement), drainage (canal opening) and gentle treatment of the tissues (occlusal reduction and teeth splinting) are the principles of surgery. This is a representative case report of conservative care by the early endodontic drainage of infected teeth in the line of a mandibular fracture.
Debridement ; Drainage ; Mandibular Fractures ; Tooth ; Tooth, Nonvital ; Wound Infection

OBJECTIVETo investigate the influence of post-core structure on the strength of endodontically treated and crowned teeth with or without a 2.0 mm dentine ferrule.

METHODSA total of 60 recently extracted human maxillary central incisors were endodontically treated and randomly divided into five groups of 12. They were given following treatments: Group A, endodontically treated; Group B, endodontically treated and crowned (PFM); Group C, cast metal post-core with 2.0 mm dentine ferrule and crowned (PFM); Group D, cast metal post-core with no dentine ferrule and crowned (PFM); Group E, prefabricated post and composite core with 2.0 mm dentine ferrule and crowned (PFM). All specimens were stored at 100% humidity at room temperature for 30 days before testing. Each specimen was in a special jig on the MTS 810 universal material testing machine and subjected to a load at a 135-degree angle to the long axis until failure, with crosshead speed of 0.02 cm/minute. Analysis of variance followed by the Newman-Keuls pairwise multiple comparison tests was used to compare the results.

RESULTSThere was a statistically significant difference between different restorative methods. The cast metal post-core with 2.0 mm dentine ferrule and crowned teeth had the highest fracture strength (1793.59 +/- 387.93N), followed by endodontically treated intact teeth (1466.68 +/- 240.11N). No significant difference in the fracture strength was found among the other three groups (958.49 +/- 286.02N; 992.98 +/- 291.00N; 994.94 +/- 285.04 N). There was a statistically significant difference in the fracture resistance between crowned teeth with and without 2.0 mm dentine ferrule (P < 0.01).

CONCLUSIONSNot all post-core structure could improve the strength of endodontically treated teeth. The dentine ferrule can effectively improve the fracture resistance of endodontically treated and crowned teeth.

Theoretically, if the odontoblastic layer on the pulpal surface of the dentin is removed, it is impossible to find nucleus after the teeth has undergone endodontic therapy. So dentin does not contain genomic DNA. But it is in existence the possibility that blood permeates into the dentin by endodontic therapy and trauma. Therefore DNA in blood can be detected from the dentin layer. The purpose of this investigation is to evaluate the possibility of individual identification after detection of DNA in the dentin of endodontic created teeth. The authors isolated the human DNA from 40 endodontic treated teeth, performed AmpFLPs by PCR and electrophoresed for detection of STR loci F13A01, LPL gene and X-Y homologous amelogenin gene. The following results were obtained: 1) DNA extraction was possible in 19 endodontic treated teeth out of 40. 2) Sex determination was possible in 12 endodontic treated teeth out of 40 by detection of X-Y homologous amelogenin gene 3) F13A01 locus was detected in 6 endodontic treated teeth out of 40, observed 4 alleles(3.2, 4, 5, 6) and 5 genotypes(3.2-3.2, 3.2-4, 3.2-5, 4-5, 6-6). 4) LPL locus was detected in 7 endodontic treated teeth out of 40, observed 3 alleles(10, 11, 12) and 3 genotypes(10-10, 10-12, 11-12). From the above results DNA extraction, sex determination, amplification of STR locus F13A01, and LPL gene were possible in the endodontic treated teeth and it was suggested that endodontic treated teeth were useful and applicatable as molecular biological samples for individual identification.
Amelogenin* ; Dentin* ; DNA ; Humans ; Odontoblasts ; Polymerase Chain Reaction ; Tooth ; Tooth, Nonvital*

OBJECTIVETo analyze the stress magnitude and distribution of remaining dentin in posterior residual root restored with post-core crown by three-dimension finite element methods. The variables were number, length and material of post.

METHODSThe models of residual root of maxillary first molar restored with post-core crown were created by CT scanning, Mimics software and Abaqus software. Different number, length and material of posts were used in the modeling. The post was cemented with zinc-phosphate cement. A load of 240 N was applied to the occlusal surface in vertical direction and tensile, shear, and Von mises stresses were calculated.

RESULTSThe maximum stresses on remaining dentin changed irregularly as the number and length of post. The maximum stresses on remaining dentin decreased slightly as elastic modulus of the material of post increase.

CONCLUSIONThe number, length, material of post have influence on magnitude and distribution of stress.

OBJECTIVEThis study aims to compare the fracture resistance of teeth restored with different post and core systems by cyclic loading test and to predict long-term effects.

METHODSA total of 15 recently extracted mandibular premolars without crowns were endodontically treated. The teeth were randomly divided into three groups with five teeth in each group. Group A, teeth restored with cast metal post and core. Group B, teeth with fiber post and resin core. Group C, teeth with resin filling. All of the teeth were restored with full-cast metal crowns. The specimens were exposed to 300,000 cyclic loadings in a cyclic loading machine and 1,000 thermal cycles between 5 and 55 °C. All of the samples were loaded in AG-IS mechanical testing machine with a compressive load until fracture occurred. The fracture load and the fracture mode of each tooth were recorded.

RESULTSThe fracture resistance in group B and C were higher than that of the cast metal post and core restoration (P < 0.05). Repairable fractures were observed in group B and C, whereas unrestorable and catastrophic fractures were found in group A.

CONCLUSIONFiber post and resin filling is a good choice to restore endodontically treated teeth.

Coronal restoration of endodontically treated teeth may be viewed as one of the main parameters that influence the outcome of endodontic treatment. The purposes of restoring endodontically-treated teeth include preventing recontamination of the root canal system and periapical area, replacing the compromised dental hard tissue, restoring the coronal morphology and function, providing necessary strength for the restoration/tooth complex for functional stress, and avoiding crown and/or root fracture. This article reviewed recent researches on the restoration of endodontically treated teeth, provided evidence for clinical practice on topics as when to restore them, basic principles to be considered during treatment planning, and specific restoration options for both anterior and posterior teeth under different functional occulsal load conditions. Several issues should be taken into account during the decision making process, such as remaining tooth tissue, functional masticatory forces, comprehensive oral rehabilitation, and esthetic requirements.
Decision Making ; Dental Restoration, Permanent ; Humans ; Root Canal Therapy ; Tooth Crown ; Tooth, Nonvital

OBJECTIVETo compare the fracture resistance and failure modes of endodontically treated human upper premolars restored with different post-core systems.

METHODS32 extracted human upper premolars were endodontically treated and crowns were sectioned at 2 mm above the labial cement enamel junction (CEJ). The teeth were randomly and equally divided into 4 groups: Group A, teeth restored with cast metal post and metal crown; group B, Tenax Fiber White fiber post and metal crown; group C, EverStick fiber post 1.5 mm in diameter and metal crown; group D, EverStick fiber post 1.5 mm in diameter and add another 1.2 mm diameter EverStick fiber post and metal crown. All the teeth were embedded in acrylic resin blocks, and were subjected to a compressive load at 1 mm/min crosshead speed which delivered at a 45 degrees to the long axis until the first sign of failure was noted. The fracture load and the mode of fracture were recorded.

RESULTSFracture resistances of the four groups of restored teeth were not significantly different (P>0.05). However, fracture modes in fiber post groups were nearer to CEJ than cast metal post group.

CONCLUSIONFracture resistance of endodontically treated teeth restored with EverStick fiber post is enhanced that it can meet the clinical need, although the flexural resistance of EverStick fiber post itself is the weakest. Fracture modes of all fiber post groups are more favorable than cast metal post group.

OBJECTIVETo compare the different restorations of endodontically treated premolars, and to choose the best method.

METHODS10 pairs of symmetry maxillary first premolars were collected from 10 patients, and randomly divided into 2 groups. Every pair received different treatment accordingly. The test group was set up the medial-occlusal cavities model under the same standard. The 10 pairs teeth were test by instron 4302 universal test machine in speed of 1.00 mm/min until broken up and the top load was recorded. The load angle was 45 degree to the long axis of the teeth, as the load was pointed to the middle of the lingual surface on the buccal cusp. The records were analyzed by paired samples t test.

RESULTSBased on the medial-occlusal cavities, the fracture strength of the full crowned teeth was lower than the full natural teeth, and the fracture strength of the post-crowned teeth was higher than the full natural teeth.

CONCLUSIONFrom the point of biomechanics, the different trauma of the endodontically treated teeth fits to different restorations. The medial-occlusion cavities fit the post-crown restoration mostly.