Risk score algorithm for treatment of persistent apical periodontitis.

Persistent apical periodontitis related to a nonvital tooth that does not resolve following root canal treatment may be compatible with health and may not require further intervention. This research aimed to develop a Deterioration Risk Score (DRS) to differentiate lesions requiring further intervention from lesions likely to be compatible with health. In this cross-sectional study, patient records (2003-2008) were screened for root-filled teeth with periapical radiolucency visible on periapical radiographs taken at treatment and at recruitment at least 4 yr later. The final sample consisted of 228 lesions in 182 patients. Potential demographic and treatment risk factors were screened against 3 categorical outcomes (improved/unchanged/deteriorated), and a multivariate independent multinomial probit regression model was built. A 5-level DRS was constructed by summing values of adjusted regression coefficients in the model, based on predicted probabilities of deterioration. Most lesions (127, 55.7%) had improved over time, while 32 (14.0%) remained unchanged, and 69 (30.3%) had deteriorated. Significant predictors of deterioration were as follows: time since treatment (relative risk [RR]: 1.11, 95% confidence interval [CI]: 1.01-1.22, p = .030, rounded beta value = 1, for every year increase after 4 yr), current pain (RR: 3.79, 95% CI: 1.48-9.70, p = .005, rounded beta value = 13), sinus tract present (RR: 4.13, 95% CI: 1.11-15.29, p = .034, rounded beta value = 14), and lesion size (RR: 7.20, 95% CI: 3.70-14.02, p < .001, rounded beta value = 20). Persistent apical periodontitis with DRS <15 represented very low risk; 15-20, low risk; 21-30, moderate risk; 31-40, high risk; and >40, very high risk. DRS could help the clinician identify persistent apical periodontitis at low risk for deterioration, and it would not require intervention. When validated, this tool could reduce the risk of overtreatment and contribute toward targeted care and better efficiency in the timely management of disease.

Fracture strength and fracture patterns of root-filled teeth restored with direct resin composite restorations under static and fatigue loading.

AIM: To assess fracture strength and fracture patterns of root-filled teeth with direct resin composite restorations under static and fatigue loading. METHODOLOGY: MOD cavities plus endodontic access were prepared in 48 premolars. Teeth were root filled and divided into three restorative groups, as follows 1) resin composite; 2) glass ionomer cement (GIC) core and resin composite; and 3) open laminate technique with GIC and resin composite. Teeth were loaded in a servohydraulic material test system. Eight samples in each group were subjected to stepped fatigue loading: a preconditioning load of 100 N (5000 cycles) followed by 30,000 cycles each at 200 N and higher loads in 50-N increments until fracture. Noncycled teeth were subjected to a ramped load. Fracture load, number of cycles, and fracture patterns were recorded. Data were analyzed using two-way analysis of variance and Bonferroni tests. RESULTS: Fatigue cycling reduced fracture strength significantly (p<0.001). Teeth restored with a GIC core and a laminate technique were significantly weaker than the composite group (379±56 N, 352±67 N vs 490±78 N, p=0.001). Initial debonding occurred before the tooth underwent fracture. All failures were predominantly adhesive, with subcrestal fracture of the buccal cusp. CONCLUSIONS: Resin composite restorations had significantly higher fracture strength than did other restorations. Fatigue cycled teeth failed at lower load than did noncycled teeth.

Enhancing the bond of a resin-based sealer to root dentine.

AIM: To evaluate whether application of a total-etch/separate adhesive layer can enhance the bond of a UDMA-based sealer to dentine. METHODOLOGY: The root canals of 20 decoronated maxillary premolar teeth with two canals were prepared to size 35-45, 0.04 taper using rotary NiTi instruments. The canals of each tooth were treated with application of either a total-etch/separate adhesive or the manufacturer-recommended primer, before root filling with sealer plus matching master cone using warm vertical compaction. After setting, roots were sectioned perpendicular to the long axis to obtain 1-mm-thick slices, and the root filling was subjected to the push-out test using a plunger closely matched to canal diameter. The roots of another 15 single-rooted premolars were sectioned in a bucco-lingual direction, and the cut surfaces were ground flat for microshear bond strength testing. One-half of the specimens were coated with a separate total-etch/adhesive layer, and then, a cylinder of sealer cement 1 mm diameter × 1.5 mm high was bonded to the prepared surface of all specimens. Microshear bond strength was measured in a universal testing machine after 48 h. Data were analysed using anova and paired t-tests, with significance set at P < 0.05. RESULTS: Use of a separate total-etch/adhesive markedly increased both microshear bond strength and push-out strengths compared with standard primer (P < 0.001). CONCLUSION: Application of a separate adhesive layer significantly increases bond strength of UDMA-based sealers to root dentine.

Assessment of laminate technique using glass ionomer and resin composite for restoration of root filled teeth.

OBJECTIVE: To evaluate the open laminate technique using glass ionomer cements (GIC) in association with a low shrink composite for restoring root filled premolars. METHODS: Extensive MOD cavities plus endodontic access and root filling were performed in intact extracted maxillary premolars. Three restoration types were evaluated: (1) resin composite alone; (2) resin-modified GIC (RM-GIC) open laminate plus resin composite; (3) conventional GIC open laminate plus resin composite (n=8 for all groups and tests). Three tests were conducted to assess restorations: (A) inward cusp deflection during light curing, using DCDTs; (B) fracture strength using a ramped oblique load at 45° to the long axis in a servohydraulic testing machine in comparison with intact and unrestored teeth; (C) proximal marginal leakage using methylene blue dye and the effect of thermocycling. Data were analysed using 1-way ANOVA for cuspal deflection and fracture strength and Fisher's exact test for leakage. RESULTS: Laminate restorations resulted in significantly less cuspal deflection compared with resin composite (4.2±1.2 µm for RM-GIC and 5.1±2.3 µm for conventional GIC vs. 12.2±2.6 µm for composite, P<0.001). Fracture strength was not significantly different among all groups. Failure with all restorations was predominantly adhesive at the tooth-restoration interface. The two laminate groups showed significantly better marginal seal than composite alone, but sealing ability of conventional GIC deteriorated after thermocycling. CONCLUSIONS: Laminate restoration of root filled teeth had beneficial effects in terms of reducing cuspal deflection and marginal seal, with acceptable fracture strength.

Survival of rat functional dental pulp cells in vascularized tissue engineering chambers.

Regenerative endodontics aims to preserve, repair or regenerate the dental pulp tissue. Dental pulp stem cells, have a potential use in dental tissue generation. However, specific requirements to drive the dental tissue generation are still obscured. We established an in vivo model for studying the survival of dental pulp cells (DPC) and their potential to generate dental pulp tissue. DPC were mixed with collagen scaffold with or without slow release bone morphogenic protein 4 (BMP-4) and fibroblast growth factor 2 (FGF2). The cell suspension was transplanted into a vascularized tissue engineering chamber in the rat groin. Tissue constructs were harvested after 2, 4, 6, and 8 weeks and processed for histomorphological and immunohistochemical analysis. After 2 weeks newly formed tissue with new blood vessel formation were observed inside the chamber. DPC were found around dentin, particularly around the vascular pedicle and also close to the gelatin microspheres. Cell survival, was confirmed up to 8 weeks after transplantation. Dentin Sialophosphoprotein (DSPP) positive matrix production was detected in the chamber, indicating functionality of dental pulp progenitor cells. This study demonstrates the potential of our tissue engineering model to study rat dental pulp cells and their behavior in dental pulp regeneration, for future development of an alternative treatment using these techniques.

Fracture resistance of roots filled with gutta-percha or RealSeal®.

AIM: To evaluate the vertical root fracture resistance of maxillary central incisors filled with different root filling materials and sealers. METHODOLOGY: Forty maxillary central incisor root canals were instrumented and divided randomly into four groups. Each group was filled using lateral compaction, with gutta-percha and AH Plus, gutta-percha and RealSeal(®) sealer, RealSeal(®) cone and RealSeal(®) sealer, or RealSeal(®) cone and AH Plus, respectively. The roots were loaded vertically by a conical spreader tip inserted into the canal and attached to an Instron testing machine until root fracture occurred. The load at fracture and the pattern of fracture were recorded. Mechanical properties of both core materials were tested under compressive loading. Results were analysed statistically by two-way analysis of variance and post hoc Tukey's tests. An independent sample t-test was used to compare the mechanical properties of the filling materials. RESULTS: Load at fracture of roots filled with gutta-percha and AH Plus (255 ± 74 N) and gutta-percha and RealSeal(®) sealer (237 ± 38 N) was significantly greater than those filled using the RealSeal(®) system (163 ± 29 N) and RealSeal(®) cone with AH Plus sealer (134 ± 17 N). Most fracture lines were in a bucco-lingual direction. In compressive tests of the core materials, RealSeal(®) had greater flow in response to load than gutta-percha, suggesting more efficient transmission of forces to the canal wall in the fracture tests. CONCLUSIONS: The lower fracture resistance of roots filled using RealSeal(®) is probably the result of more efficient transmission of forces within the canal, rather than a direct effect of the material itself.

Fracture strength and fracture patterns of root filled teeth restored with direct resin restorations.

OBJECTIVE: To compare fracture characteristics of root-filled teeth with variable cavity design and resin composite restoration. METHODS: 80 extracted intact maxillary premolars were divided randomly into eight groups; (1) intact teeth; (2) unrestored MOD cavity; (3) unrestored MOD cavity plus endodontic access through the occlusal floor; (4) unrestored MOD plus endodontic access with axial walls removed; (5) MOD restored with resin composite; (6) MOD plus endodontic access, resin composite; (7) MOD plus extensive endodontic access, resin composite; (8) MOD plus extensive endodontic access, GIC core and resin composite. A ramped oblique load was applied to the buccal cusp in a servohydraulic testing machine. Fracture load and fracture patterns were recorded. Fracture loads were compared statistically using 1-way ANOVA, with Dunnett test for multiple comparisons. RESULTS: Unrestored teeth became progressively weaker with more extensive preparations. Endodontic access confined within the occlusal floor did not significantly affect strength compared to an MOD cavity. Loss of axial walls weakened teeth considerably [292+80N vs 747+130N for intact teeth]. Restoration increased the strength of prepared teeth particularly in teeth without axial walls. Teeth with a GIC core were not significantly weaker than intact teeth [560+167N]. Failures were mostly adhesive at the buccal interface, with the fracture propagating from the buccal line angle of the occlusal floor (MOD and MOD plus access groups) or of the proximal box (axial wall removed). CONCLUSIONS: Direct restorations increased fracture resistance of root filled teeth with extensive endodontic access. Both restored and unrestored teeth showed similar fracture patterns.

Multiple idiopathic cervical resorption: case report and discussion of management options.

AIM: To present a case of cervical root resorption affecting all teeth and resulting in multiple tooth loss. SUMMARY: A healthy 33-year-old Chinese male, with no contributory medical or family/social history, presented with generalized cervical root resorption. Lesions varied in severity amongst teeth and even involved an impacted third molar. All cervical root surfaces were affected and lesions often extended coronally, undermining enamel. CBCT demonstrated that the lesions were more extensive and more widely distributed than was seen using conventional radiography. Bone extended into many resorptive defects but without clinical evidence of ankylosis. Periodontal probing, pulp testing, percussion sound and mobility were within normal limits. Key learning points • Aetiology of the generalized idiopathic cervical root resorption is uncertain. • Management is complex, and options have included surgical exposure and restoration of affected sites, extraction and submergence of affected roots. • A staged approach involving early intervention with restoration of resorptive defects, followed by progressive extraction and replacement with implant-supported prostheses is recommended.

The effect of ultrasonically activated irrigation on reduction of Enterococcus faecalis in experimentally infected root canals.

AIM: To investigate the ability of an ultrasonically activated irrigating system to eliminate bacteria from the canal wall and dentinal tubules of extracted teeth. METHODOLOGY: One hundred and thirty roots of intact human teeth were inoculated with Enterococcus faecalis for 4 weeks. The straight roots were randomly allocated to a baseline group (n=25) or subjected to routine cleaning and shaping procedures (n=105). Two sub-groups of prepared canals were then additionally exposed either to ultrasonic irrigation with 1% sodium hypochlorite (NaOCl) for 1 min (n=35) or to 1 week of intracanal medication with calcium hydroxide [Ca(OH)(2)] (n=35). All roots were processed for light microscopy (Brown and Brenn stain) (n=28) or scanning electron microscopy (n=7). Triplicate histological sections from each of the apical, middle and coronal thirds were scored for bacterial presence using pre-defined criteria. RESULTS: Baseline bacterial penetration resulted in an average depth of tubule invasion of 151 µm. Routine canal preparation failed to eliminate bacteria consistently from either the canal wall or within tubules. Ultrasonic irrigation and medication with Ca(OH)(2) consistently eliminated bacteria from the canal wall (P<0.001) compared with baseline and routine treatment, and more frequently from dentinal tubules than routine canal preparation alone (P<0.01). Ultrasonic irrigation was as effective in bacterial reduction as 1 week of intracanal medication with Ca(OH)(2), but neither led to complete bacterial elimination in all roots. CONCLUSIONS: Ultrasonically activated irrigation for 1 min with 1% NaOCl after canal preparation in straight root canals is potentially an effective supplementary step in microbial control.

Australian endodontists' perceptions of single and multiple visit root canal treatment.

AIM: To ascertain endodontist's point of view (treatment philosophy, rationale and preference) regarding single- and multiple-visit root canal treatment. To identify the basis on which the choice is made and how the information necessary for the choice is acquired. METHODOLOGY: Endodontists registered with the dental practice board of every state in Australia were contacted, and if they agreed to participate, they were interviewed either face to face or by telephone. The following topics were addressed in an interview lasting 15 to 20 min: demographics, current clinical procedures, treatment rationales and preference. A hypothetical scenario was posed to investigate which treatment regimen they would prefer to deliver if biological concerns were eliminated from consideration. RESULTS: Fifty-two endodontists (71% of all Australian endodontists) agreed to participate in the study. Almost all (51/52) participants had performed single-visit root canal treatment, but very few routinely performed it. A majority of participants were willing to provide single-visit treatment where patients had time constraints, and in vital cases (including elective endodontics). The most powerful factor of influencing practice change was interpersonal contact with colleagues. Publications in academic journals have a weak influence in practice change. CONCLUSIONS: Australian endodontists strongly prefer multiple-visit over single-visit root canal treatment even in cases where biological concerns are not an issue. Operator preference rather than biological or patient considerations appear to be the primary determinant of treatment choice.

The effect of resin-based sealers on fracture properties of dentine.

AIM: To determine whether resin-based sealer cements are able to strengthen root dentine, as measured by work of fracture (Wf), micro-punch shear strength (MPSS) and resistance to vertical root fracture (VRF). METHODOLOGY: One hundred and twenty extracted premolar teeth were randomly assigned amongst four treatments before testing: intact, root canals prepared but unfilled, or root filled using epoxy- or urethane dimethacrylate (UDMA)-based sealer (plus core material). Samples were then prepared for measuring Wf, MPSS or VRF using standard test procedures. Data were analyzed using one-way anova with significance set at P < 0.05. RESULTS: For all three tests, root canals filled using epoxy resin-based sealer were not statistically significantly different compared with UDMA resin (P = 1 for Wf, P = 0.7 for MPSS and P = 0.12 for VRF), or different from both sound and prepared dentine (P > 0.05). There was also no significant difference between sound dentine and prepared dentine for both Wf (P = 0.92) and resistance to VRF (P = 1). CONCLUSIONS: Neither epoxy nor UDMA resins used as sealer cements enhanced fracture resistance of root dentine when placed within root canals of extracted teeth.

Dentinal tubule invasion and adherence by Enterococcus faecalis.

AIM: To investigate dentinal tubule invasion and the predilection of Enterococcus faecalis for dentinal tubule walls. METHODOLOGY: The invasion of dentinal tubules in extracted human teeth by E. faecalis was measured ex vivo after 8 weeks of incubation. The canal walls of 16 root sections were either intact or instrumented with or without smear layer present. Extent and maximum depth of tubule invasion were assessed histologically and compared between groups. In the adherence study, 44 vertically split root samples were prepared to expose longitudinally aligned dentinal tubules and fractured orthodentine (OD). Surfaces were exposed to E. faecalis (erythromycin resistant strain, JH2-2 carrying plasmid pGh9:ISS1) and incubated aerobically for 2 h. Samples were processed for analysis using scanning electron microscopy. Bacterial adhesion to tubule walls versus fractured OD was calculated as number of cells per 100 microm(2). RESULTS: The strain of E. faecalis used in this study showed moderate to heavy tubule invasion after 8 weeks. In the adhesion studies, significantly more bacteria adhered to fractured OD than to dentinal tubule walls (ANOVA, P < 0.001). With respect to the tubule wall, adherence was greater in inner versus outer dentine (P = 0.02) and greater when bacterial adhesion was tested in chemically defined medium than in phosphate-buffered saline (ANOVA, P < 0.001). CONCLUSIONS: Although E. faecalis readily invaded tubules, it did not adhere preferentially to tubule walls. Initial colonization of dentinal tubules by E. faecalis may depend primarily on other factors.

The technical quality of nonsurgical root canal treatment performed by a selected cohort of Australian endodontists.

AIM: To investigate the technical quality of nonsurgical root canal treatment performed by endodontists in Melbourne, Australia. METHODOLOGY: Clinical and radiographic records of 100 sequential nonsurgical patients were obtained from each of six endodontists working in private practice. The following variables were analysed: proximity of root filling to radiographic apex; homogeneity and radiodensity of root filling; lateral adaptation of the root filling to the canal walls; taper; extrusion of material; small, appropriate or excessive apical enlargement; presence of lateral canals; transportation; procedural errors. The radiographs were assessed by three independent evaluators. Exploratory data analysis was undertaken using simple frequencies and cross-tabulations. A generalised linear mixed model (GLMM) was used for the formal statistical modelling. RESULTS: Of the 1351 canals that were examined, 91.7% were filled within 2 mm of the radiographic apex and 74% were within 1 mm. Homogeneity and adequate density were found along the entire length of the canal in 86.1% and 88.6% of cases respectively. Lateral adaptation was adequate in 95.6% of cases and the taper was 'smooth and continuous' in 83.8% of roots. No and/or small extrusion of sealer was noted in 98.3% of cases. Apical enlargement was 'appropriate' in 85% of roots. Both transportation (1.1%) and procedural errors (1.3%) were rare occurrences. CONCLUSIONS: The technical quality of root fillings performed by endodontists in Melbourne, Australia complied with current guidelines in 77.4%-91.0% of roots. All variables examined confirmed high levels of technical proficiency. There were very few instances of canal transportation and/or procedural errors.

Thermal transfer in extracted incisors during thermal pulp sensitivity testing.

AIM: To measure the temperature distribution within tooth structure during and after application of thermal stimuli used during pulp sensitivity testing. METHODOLOGY: Extracted intact human maxillary anterior teeth were investigated for temperature changes at the labial enamel, the dentino-enamel junction (DEJ) and pulpal surface during and after a 5-s application of six different thermal stimuli: hot water (80 degrees C), heated gutta-percha (140 degrees C), carbon dioxide dry ice (-72 degrees C), refrigerant spray (-50 degrees C), ice stick (0 degrees C) and cold water (2 degrees C). J-type thermocouples and heat conduction paste were used to detect temperature changes, together with a data acquisition system (Labview). Data were analysed using analysis of variance, with a confidence level of P < 0.05. RESULTS: Temperature change was detected more quickly at the DEJ and pulpal surface with the application of hot water, heated gutta-percha and refrigerant spray than with carbon dioxide dry ice and ice (P < 0.05). Cold water and refrigerant spray were in the same range in terms of time to detect temperature change at both the DEJ and pulpal surface. Thermal stimuli with greater temperature difference from tooth temperature created a greater thermal gradient initially, followed by a greater temperature change at the DEJ and the pulpal surface. In this regard, ice and cold water were weaker stimuli than others (P < 0.05). CONCLUSIONS: Thermal stimuli used in pulp testing are highly variable in terms of temperature of the stimulus, rate of thermal transfer to the tooth and extent of temperature change within tooth structure. Overall, dry ice and refrigerant spray provide the most consistent stimuli, whereas heated gutta-percha and hot water were highly variable. Ice was a weak stimulus.

The prevalence of postoperative pain and flare-up in single- and multiple-visit endodontic treatment: a systematic review.

AIM: The aim of this systematic review was to assess the evidence regarding postoperative pain and flare-up of single- or multiple-visit root canal treatment. METHODOLOGY: CENTRAL, MEDLINE and EMBASE databases were searched. Reference lists from identified articles were scanned. A forward search was undertaken on the authors of the identified articles. Papers that had cited these articles were also identified through Science Citation Index to identify potentially relevant subsequent primary research. REVIEW METHODS: The included clinical studies compared the prevalence/severity of postoperative pain or flare-up in single- and multiple-visit root canal treatment. Data in those studies were extracted independently. RESULTS: Sixteen studies fitted the inclusion criteria in the review, with sample size varying from 60 to 1012 cases. The prevalence of postoperative pain ranged from 3% to 58%. The heterogeneity amongst included studies was far too great to conduct meta-analysis and yield meaningful results. CONCLUSION: Compelling evidence indicating a significantly different prevalence of postoperative pain/flare-up of either single- or multiple-visit root canal treatment is lacking.

Push-out bond strengths of the dentine-sealer interface with and without a main cone.

AIM: To evaluate the push-out bond strength of the dentine-sealer interface with and without main cone for three resin sealers. METHODOLOGY: Thirty extracted maxillary premolar teeth with two separate canals were prepared using 0.04 taper Profile instruments to size 35-45. Teeth were divided into three groups for filling using AH Plus, EndoREZ or Resilon sealers. In each tooth, one canal was filled with a matching single-cone technique, and other was filled with sealer alone. A 1 mm slice of mid-root dentine was prepared for the push-out test. Failure modes after push-out were examined under microscopy and field emission-scanning electron microscopy. Data were analysed using two-way anova and paired t-tests, with significance set at P < 0.05. RESULTS: Overall, the epoxy resin-based sealer provided the highest push-out bond strengths. Push-out bond strengths were significantly higher (P < 0.001) when canals were filled with sealer alone than those filled with main cone and sealer (AH Plus 6.6 and 2.0 MPa, respectively; Resilon 3.4 and 0.4 MPa; EndoREZ 0.9 and 0.4 MPa). Sealers appeared to behave differently as thin films in association with a main cone, compared with bulk material. They failed in cohesive mode within the thin film, leaving a layer of sealer on the canal surface. Bulk sealer showed predominantly adhesive failure at the dentine-sealer interface, with a clean dentine wall and with resin tags either partially pulled out or sheared off at the interface. CONCLUSION: Push-out bond strengths of resin sealers were much lower when the sealer was present as a thin layer.

Penetration of dentinal tubules by endodontic sealer cements in extracted teeth and in vivo.

AIM: To compare the depth and consistency of penetration of three different root canal sealer cements into dentinal tubules in extracted teeth and to measure the penetration of an epoxy resin-based sealer cement in vivo. METHODOLOGY: Root canals of 50 extracted human pre-molar teeth were prepared and obturated using three different sealer cements based on epoxy resin (AH26), zinc oxide eugenol (Pulp Canal Sealer EWT) and methacrylate resin (EndoREZ). Five teeth filled without sealer were used as controls. Teeth were sectioned and prepared for observation using scanning electron microscopy. A further 12 teeth with a history of successful root filling and subsequent extraction were collected and sectioned. The depth of sealer penetration into dentinal tubules was measured and the consistency and appearance of the sealer within the tubules observed. RESULTS: AH26 demonstrated the deepest penetration (1337 microm), followed by EndoREZ (863 microm) and Pulp Canal Sealer EWT (71 microm). The difference in penetration between all sealer groups was found to be statistically significant (P < 0.05). The resin-based sealers appeared to penetrate tubules more consistently. In the clinical cases, all teeth demonstrated sealer penetration to varying depths (98-1490 microm). CONCLUSIONS: The depth and consistency of dentinal tubule penetration of sealer cements appears to be influenced by the chemical and physical characteristics of the materials. Resin-based sealers displayed deeper and more consistent penetration. Penetration depths observed for the epoxy resin-based sealer in vivo were consistent with that found in the experimental model.

Temperature change, dentinal fluid flow and cuspal displacement during resin composite restoration.

Dentin-bonding agents and resin composite materials typically require light activation for polymerization. Light curing generates heat, which may influence dentinal fluid flow (DFF) and cuspal displacement. This study investigated the relationship among temperature increase, DFF and cuspal displacement in extracted human maxillary premolars with a mesial occlusal distal (MOD) cavity preparation. Two types of curing light were compared. Temperature changes were measured using thermocouples located on the occlusal cavity floor and at the pulp-dentine junction, during polymerization of bonding agent and resin composite material. DFF and cuspal displacement were measured simultaneously using automated flow measurement apparatus and direct current differential transformers respectively. Temperature increases of up to 15 degrees C were recorded during the restoration procedures. A quartz tungsten halogen (QTH) unit produced a significantly greater temperature increase than a light-emitting diode unit and curing of the bonding agent generated less temperature increase than curing of the resin composite. Heating due to exothermic reaction during polymerization of bonding agent and resin was not significantly different between light sources or between bonding and curing (P > 0.05). The QTH unit produced both greater inward fluid flow and cuspal displacement during the irradiation of bonding agent and resin composite than the light-emitting diode unit. There was not a simple relationship between temperature increase, fluid movement and cuspal displacement. From a clinical point of view, the light-emitting diode unit can be considered preferable to the QTH light, because it caused significantly smaller temperature increase, fluid shift and cuspal displacement.

Treatment planning the endodontic case.

Following a definitive diagnosis of the need for root canal treatment, the treatment planning stage should be straightforward if a logical sequence of decision-making is followed. Very few contra-indications exist for providing root canal treatment, but the planning must include several aspects. Firstly, is root canal treatment best for the patient to maintain a functional dentition long term? Secondly, who should provide the treatment? Thirdly, what are the restorative options that will ensure the best long-term prognosis? The sequencing of root canal treatment generally occurs early in a typical treatment plan, and prompt restoration after treatment is crucial to long-term survival of the tooth.