Post and core systems, refinements to tooth preparation and cementation

Assessing dentists' knowledge and experience in restoring endodontically treated teeth using post & cores

OBJECTIVES

The restoration of endodontically, heavily filled teeth has been a challenge for the dental profession for decades. The aims of this study were to investigate dentists' experience and knowledge in the use of post & core when restoring endodontically treated teeth.

METHOD

This was a mixed method study incorporating quantitative and qualitative data collection. An online questionnaire was developed and distributed, comprised of 18 questions. It was calculated that 93 respondents were needed to validate the study of which 60% should meet a minimum knowledge requirement.

RESULTS

173 respondents completed the questionnaire. 109 (63% (95%CI56%,70%) demonstrated proficient knowledge of post & core restorations. Recent graduates were more likely to follow current guidelines (F = 4.570: P<0.034). As the age of respondent dentists increases the number of posts placed (F = 18.85; p<0.001) and the perceived confidence level increases (Spearman's Rho 0.43: P<0.01). Experience of postgraduate education also positively influenced clinical confidence.

CONCLUSION

The placement of post & cores is influenced by age. Confidence is also influenced by age. More evidence on post usage is required and several questions remain to be answered on what drives decision making and perceived long-term success.

CLINICAL SIGNIFICANCE

There is a general acceptance of when a post and core restoration should be used. Clinician experience and age can have an impact on what type of restorations are used. Fibre posts are more commonly used due their accessibility and cost.

Effect of MTA versus CEM apical plugs on fracture resistance of endodontically treated simulated immature teeth restored with cast metal posts: an in-vitro study

BACKGROUND

Endodontically treated immature teeth which are restored with cast metal posts are of the most susceptible teeth to fracture. An apical plug is usually used as root end filling in order to seal the wide apical foramen. The current study was performed to evaluate the effect of different apical plug materials (MTA and Calcium enriched mixture cement) at varied thicknesses on fracture resistance of teeth restored with cast metal posts.

METHODS

A total of 40 extracted intact single-rooted human mandibular premolars (removed for orthodontic reasons) were used in the study. The coronal part of each tooth was removed and root canal preparation was performed. A size 4 Gates Glidden drill was used to enlarge the canal and was passed through the apical foramen in order to simulate an immature apex. Samples were randomly divided into 5 groups (n = 8) according to apical plug (control group: No plug, group MTA5: 5 mm MTA plug, group CEM5: 5 mm CEM plug, group MTA3: 3 mm MTA plug, group CEM3: 3 mm CEM plug). Post-space preparations were performed and cast metal post-and-cores were fabricated and cemented. Fracture resistance was assessed using a universal testing machine. Fracture thresholds were recorded and data were analyzed using One-way ANOVA and Dunnett's T3 tests with significance level at P value < 0.05.

RESULTS

The analysis showed a significant difference of fracture resistance between groups (P value < 0.05). The mean fracture resistance of samples in control group was significantly lower than MTA5 (P value = 0.003). There was no significant difference between other groups (P value > 0.05).

CONCLUSIONS

Within the limits of this study, the evidence indicated that placement of a 5 mm MTA apical plug increased the fracture resistance in simulated immature teeth which are restored with cast metal posts, compared to control group (gutta-percha and sealer). While the results were not as promising for a 3 mm MTA apical plug or either 3 or 5 mm CEM apical plug.

Novel hollow fiber sandwich composite post system: mechanical characteristics

BACKGROUND

There is currently no consensus on the optimal post system to provide effective long-term results. We used an engineering approach to investigate the mechanical properties of a sandwich hollow carbon fiber post in synergy with a new bonding technique.

METHODS

We studied two systems - a sandwich fiber hollow post (Techole®, Isasan, Como, Italy) composed of carbon fiber incorporated in a Dpp-MOR resin mix and a traditional non-hollow post (Tech 2000®, Isasan, Como, Italy). A bi-component composite (Clearfil Core®, Kuraray, New York, NY, USA) (2.2 gcm3, 12.3 GPa) and a dual cure composite with lower density and modulus of elasticity (Clearfil DC Core®, Kuraray, New York, NY, USA) (2.0 gcm3, 10.0 GPa) were also used into hollow posts. Results from three-point bending test (N.=81), compression test (N.=78) and cut test (N.=81) were achieved.

RESULTS

In the three-point bending test there were significant differences in flexibility/bending when sandwich fiber hollow posts were filled with composite of different modulus of elasticity. Hollow sandwich posts showed also significant (P=0.000) better resistance to compression and cutting than solid posts, independently of the type of composite. Moreover, hollow posts filled plus composite with a modulus of elasticity of 12.3 GPa showed significant (P=0.000) improved resistance parameters rather than hollow posts filled with a composite of 10.0 GPa.

CONCLUSIONS

The study confirms the favorable mechanical properties of the hollow sandwich fiber post system (Techole®) and the synergistic efficacy when used in combination with the composite Clearfil DC Core® (10.0 GPa) and, especially, Clearfil Core® (12.3 GPa).

Restoration of Endodontically-Treated Anterior Teeth

Detailed consideration of a case involving the restoration of an endodontically-treated maxillary canine tooth provides opportunity to review the many different considerations and treatment options in such situations. The restoration of endodontically-treated anterior teeth must be patient-centred, applying materials and techniques best suited to achieve a successful clinical outcome.

A conservative single visit reattachment of fractured crown fragment

Injury of anterior teeth is a relatively common event that mainly affects children and adolescents. Dentists are confronted with managing dental trauma and restoring fractured teeth on a regular basis. Hence the techniques that speed and simplify the treatment, restore esthetics and improve long term success rate are considered of potential value. If an intact tooth fragment is present after trauma, immediate attachment of the incisal edge is a conservative yet, simple and aesthetic alternative. Fracture reattachment possesses challenging conservative and economically viable procedure within a single visit. The authors wuld report a case of fractured maxillary central incisor using fragment reattachment.

Parallel post-space preparation in different tooth types ex vivo: deviation from the canal centre and remaining dentine thickness

AIM

To determine the deviation of parallel-sided twist-drills during post-channel preparation and relate this to tooth type and position.

METHODOLOGY

Human teeth with single root canals were selected: maxillary second premolars (group i); maxillary lateral incisors (group ii); mandibular canines (group iii); mandibular first premolars (group iv; all groups n = 16). The teeth were reduced to 17 mm length by sectioning the crown, and the root canals prepared and filled. Microradiographs were made in two directions. The teeth were individually embedded in a gypsum jaw and placed in a phantom head. Two operators performed parallel post-space preparation (12 mm length, 1.25 mm diameter) to the following protocol: gutta-percha removal with Gates Glidden drills numbers 2 and 3 and post-space enlargement with parallel drills numbers 3, 4 and 5, consecutively. Subsequently, microradiographs were re-exposed. The original and post-operative microradiographs were digitized and superimposed, and deviation of the post-space from the filled canal and remaining dentine thickness measured.

RESULTS

Overall, the mean deviation was 0.07 mm to the mesial (95% CI: 0.01-0.12), and 0.27 mm to the buccal (95% CI: 0.18-0.35). Group ii had significantly more buccal deviation than other groups (P = 0.004-0.008). A remaining dentine thickness of <0.5 mm occurred 16 times in 14 teeth, and of <1 mm occurred 97 times in 52 teeth.

CONCLUSIONS

Deviation during parallel post-preparation was common, predominantly in mesial and buccal directions, especially in maxillary incisors. This deviation increased the risk of perforation considerably.

Clinical evaluation of root filled teeth restored with or without post-and-core systems in a specialist practice setting

AIM

To assess survival rates and complications of root-filled teeth restored with or without post-and-core systems over a mean observation period of >or=4 years.

METHODOLOGY

A total of 325 single- and multirooted teeth in 183 subjects treated in a private practice were root filled and restored with either a cast post-and-core or with a prefabricated titanium post and composite core. Root-filled teeth without post-retained restorations served as controls. The restored teeth served as abutments for single unit metal-ceramic or composite crowns or fixed bridges. Teeth supporting cantilever bridges, overdentures or telescopic crowns were excluded.

RESULTS

Seventeen teeth in 17 subjects were lost to follow-up (17/325: 5.2%). The mean observation period was 5.2 +/- 1.8 (SD) years for restorations with titanium posts, 6.2 +/- 2.0 (SD) years for cast post-and-cores and 4.4 +/- 1.7 (SD) years for teeth without posts. Overall, 54% of build-ups included the incorporation of a titanium post and 26.5% the cementation of a cast post-and-core. The remaining 19.5% of the teeth were restored without intraradicular retention. The adjusted 5-year tooth survival rate amounted to 92.5% for teeth restored with titanium posts, to 97.1% for teeth restored with cast post-and-cores and to 94.3% for teeth without post restorations, respectively. The most frequent complications included root fracture (6.2%), recurrent caries (1.9%), post-treatment periradicular disease (1.6%) and loss of retention (1.3%).

CONCLUSION

Provided that high-quality root canal treatment and restorative protocols are implemented, high survival and low complication rates of single- and multirooted root-filled teeth used as abutments for fixed restorations can be expected after a mean observation period of >or=4 years.