Radiographic Evaluation of Post-core Restorations fabricated by Dental Students at Jazan University.

AIM: Post and core procedures are important clinical methods in routine dental practice. The present research aimed to radiographically assess the quality of post seating performed by undergraduate students at the College of Dentistry, Jazan University. MATERIALS AND METHODS: A total of 343 periapical X-rays of cemented posts (170 from males and 173 from females) were assessed. The assessment covered tooth type, arch, gender, type of post, length of post in relation to the crown and root lengths, the presence of any abnormality in post space, status of the remaining gutta-percha (GP), and the presence or absence of spaces between the end of post and GP. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) program (version 21), and associations between variables were determined using chi-squared or Fisher's exact tests. RESULTS: Maxillary teeth were the most frequently restored with posts, and the majority (41%) comprised incisors. Similarly, glass fiber post (69%) and taper-shaped posts (86%) were the most used posts. The majority of posts (81.6%) featured a width one-thirds that of the root. Lengths of posts were twice (58%) or equal to (51%) crown and root length respectively. More than 55% of cases presented 3 to 5 mm of GP at their apical portion, and 29% reached more than 5 mm. Approximately 5 to 8% of assessed cases revealed widening of periodontal ligaments, presence of periapical pathologies, and deviation of posts from the canal wall. Most cases (75%) showed the absence of space between GP and the post end. CONCLUSION: Qualities of assessed post and core restorations conducted by the 6th year dental students were clinically acceptable. CLINICAL SIGNIFICANCE: Periodic evaluation to determine the quality of delivered treatments is a vital cue for health service authorities. This evaluation will improve quality of services and treatments provided by dental students to their patients under the supervision of the faculty. Results obtained will also provide authorities with a clear feedback about academic infrastructure.

Accuracy of cast posts fabricated by the direct and the indirect techniques.

STATEMENT OF PROBLEM: Patterns for custom cast posts and cores can be fabricated either by the direct or the indirect technique. Which technique is more accurate is unknown. PURPOSE: The purpose of this in vitro study was to investigate the effect of pattern fabrication technique on the accuracy of post fit. MATERIAL AND METHODS: Ten intact extracted premolar teeth with a single canal and similar dimensions received root canal treatment. The teeth were sectioned 2 mm above the cementoenamel junction. A total of 20 cast post and core patterns, 2 for each tooth, were fabricated, 10 with the direct technique and 10 with the indirect technique. Patterns were cast to produce 20 cast post and cores. Each tooth was scanned using a microcomputed tomography (µCT) system with a resolution of 14.5 µm, once with the post of the direct technique and once with the post of the indirect technique. Ct analyzer software was used to calculate the overall space between the post and canal walls and the space areas in 3 different standardized sections. The Student paired t test was used to determine any significant difference in the scores of the groups. RESULTS: The overall space between the canal walls and posts made with the direct technique ranged between 7.86 and 17.39 mm(3), with a mean value of 12.25 mm(3), whereas with the indirect technique, the space ranged between 6.68 and 18.02 mm(3), with a mean of 11.92 mm(3). No significant differences were found between the results of either technique (P>.05). CONCLUSIONS: Within the limitations of this study, neither the indirect nor direct pattern fabrication technique influenced the accuracy of post fitting.

A technique to ensure the reproducibility of a cast post and core.

The post-and-core pattern duplication technique is a simple, cost-effective, and accurate method of ensuring the reproducibility of a cast post and core. An acrylic resin pattern is fabricated for an endodontically treated tooth. The post portion of the pattern is duplicated with a polyvinyl siloxane impression material in the lower compartment of a container. The core portion is then duplicated with a polyether impression material in the upper compartment. After the original pattern has been retrieved, the duplicate resin pattern is fabricated in the provided space. This technique will improve efficiency if damage or loss of the pattern or the actual cast post and core occurs.

Influence of instrumentation techniques and irrigating solutions on bond strength of glass fiber posts to root dentin.

This study sought to evaluate how instrumentation techniques and irrigating solutions affected the bond strength of glass fiber posts. For this study, 80 human maxillary central incisors were selected. Endodontic access was obtained, root canal length was measured, and the coronal third was prepared using Gates-Glidden drills. The specimens were embedded in acrylic resin and randomly assigned to 8 groups (n = 10): manual instrumentation only (Group 1), rotary instrumentation only (Group 2), irrigation with 2.5% sodium hypochlorite (NaOCl) (Group 3), irrigation with 2% chlorhexidine (CHX) (Group 4), manual instrumentation and irrigation with 2.5% NaOCl (Group 5), manual instrumentation and irrigation with 2% CHX (Group 6), rotary instrumentation and irrigation with 2.5% NaOCl (Group 7), and rotary instrumentation and irrigation with 2% CHX (Group 8). Specimens in Groups 5-8 also received a 1 minute final rinse with ethylenediaminetetraacetic acid. Canals were filled and the specimens stored for 30 days in distilled water. The restoration material was removed down to the apical 4 mm of the root canal. The glass fiber posts were luted with resin cement and stored for 24 hours at 37°C. Specimens were subjected to a tensile strength test at a constant speed of 1.0 mm/minute and a load of 2,000 kgf. The results were analyzed by analysis of variance and Tukey's test. Irrigation with 2.5% NaOCl reduced the bond strength of fiber posts significantly (P < 0.01), while CHX showed no effect (P > 0.05). It was concluded that irrigation with 2.5% NaOCl has a negative effect on micromechanical retention of glass fiber posts, whether manual or rotary instrumentation is used.

Evaluation of Cerec endocrowns: a preliminary cohort study.

This study aimed to evaluate clinical qualities and evolution on ceramic endocrowns produced with the Cerec 3D (Sirona). Endocrowns were produced in a hospital environment and evaluated according to the FDI criteria on the day of placement and 6 months afterwards. Each item was graded from 1 (good) to 5 (bad). A global score, as well as a score for aesthetics, functioning and biological integration was assessed for each evaluation. During the 6-month evaluation period, the scores were always related to good clinical quality, except for single crown restoration. The scores did not change between the two periods of evaluation.

A flood tide of systematic reviews on endodontic posts: methodological assessment using of R-AMSTAR.

OBJECTIVES: To help the dental practitioner solve a specific clinical problem, systematic reviews (SRs) are seen as the best guide. In addition to the unmanageable quantity of SRs, however, one should be aware of their variable quality. The present review describes the methodological quality of SRs on postendodontic restorations to work out the value of these reviews for the dental practitioner. METHODOLOGY: SRs were searched in April 2012, independently and in triplicate. Post survival was used as measure of outcome. The methodological quality of included SRs was assessed with the Revised Assessment of Multiple Systematic Reviews (R-AMSTAR) checklist. Kappa statistics were used to assess reviewer agreement. RESULTS: Three hundred sixty-three papers were retrieved from the initial search. Ten SRs were included. One SR achieved a high R-AMSTAR score, whereas the other nine SRs achieved scores that indicate a substantial lack of methodological quality. Especially the items "grey literature," "combination of findings," "likelihood of publication bias," and conflict of interest" showed low R-AMSTAR scores. The three reviews with the highest R-AMSTAR scores tended to conclude that fewer failures occurred when using nonmetal posts. The reviewer agreement was excellent (kappa ranged from 0.79 to 0.85) in the R-AMSTAR classification. CONCLUSION: The approach presented revealed a lack of SRs with high methodological quality. Thus, no decisive conclusion can be drawn with respect to this topic. It appears that there is a trend for the superiority of fiber-reinforced posts. CLINICAL RELEVANCE: SRs must be of high methodological quality. This can be achieved by taking into consideration the results of this review. Improved methodological quality would make SRs more supportive for the general practitioner.

Experimental strength of restorations with fibre posts at different stages, with and without using a simulated ligament.

The aim of this study was to analyse the strength and failure mode of teeth restored with fibre posts under retention and flexural-compressive loads at different stages of the restoration and to analyse whether including a simulated ligament in the experimental setup has any effect on the strength or the failure mode. Thirty human maxillary central incisors were distributed in three different groups to be restored with simulation of different restoration stages (1: only post, 2: post and core, 3: post-core and crown), using Rebilda fibre posts. The specimens were inserted in resin blocks and loaded by means of a universal testing machine until failure under tension (stage 1) and 50º flexion (stages 2-3). Half the specimens in each group were restored using a simulated ligament between root dentine and resin block and the other half did not use this element. Failure in stage 1 always occurred at the post-dentine interface, with a mean failure load of 191·2 N. Failure in stage 2 was located mainly in the core or coronal dentine (mean failure load of 505·9 N). Failure in stage 3 was observed in the coronal dentine (mean failure load 397·4 N). Failure loads registered were greater than expected masticatory loads. Fracture modes were mostly reparable, thus indicating that this post is clinically valid at the different stages of restoration studied. The inclusion of the simulated ligament in the experimental system did not show a statistically significant effect on the failure load or the failure mode.

Accuracy of cast posts and cores using a new investigative method.

Generally, two techniques are used to fabricate a cast post and core (CPC): direct and indirect. To date, research has made no clear indication as to a comparative level of accuracy between the techniques. Therefore, the purpose of the current study was to compare the accuracy of two techniques to produce CPCs for posterior teeth using a new method. Nine endodontically treated human premolars were used for fabricating CPCs using the direct and indirect methods. A total of 18 CPCs were produced, two for each tooth, cast in high noble type IV gold. A silicone impression material was inserted into the root canals, followed by the CPCs. The remaining material in the space between the canal wall and the CPC was weighed using an electronic precision balance. By evaluating the weight of the silicon specimens, the accuracy and intimacy of fit were obtained. Since the number of samples was small, a Student t-test was used for statistical evaluation at a 90% confidence interval. The CPCs obtained by using each method were independently examined by two clinicians for proper fit. Power analysis indicated that for a 90% confidence interval and 0.8 power value, nine specimens would be necessary to achieve a statistically meaningful test. The mean value for the weight of the nine specimens obtained using the direct method was 10.3 ± 2.6 mg, while the mean value for the corresponding specimens obtained using the indirect method was significantly smaller, 7.4 ± 2.3 mg. The Student t-test value was P = 0.006. The indirect method provided CPCs with a better fit and higher accuracy. The Student t-test demonstrated a significant difference between the direct and indirect procedures. The indirect method is a valuable technique for the dental practitioner when multiple posterior cast posts and cores are necessary or interocclusal space is limited.

[Prevalence of fixed prosthesis-related periodontitis in Senegal]. / Prévalence de la prothèse fixèe et des parodontites apicales associées au Sénégal.

The purpose of this study was to determine radiographically the prevalence of periapical periodontitis in teeth restored with crown in a Senegalese population. Full mouth periapical radiographs were obtained from 208 consecutive adult patients (6234 teeth) presenting as new patients to the Dental Service of the University. The presence of crown restorations, the periapical status and technical quality of root fillings associated were evaluated. 7.69% (n = 16) of patients had at least one tooth that was crowned. The total number of crowns assessed was 0.95% (n = 59). The molars were the teeth most crowned 40.67% (n = 24) followed by anterior teeth 30.50% (n = 18) and premolars 28.81% (n = 17). All the crowned teeth had previous root canal treatment of which only 16.94% (n = 10) were acceptable. 53 % (n = 32) of the teeth had apical periodontitis (PAI > 2). Unacceptable root fillings were associated with a higher prevalence of periapical disease (p < 0.05). Crown with a post extending more than 4 millimetres from the apex were associated with more periapical lesions 64.28% (p < 0.05). The results indicate a low prevalence of crowned teeth, an absence of vital preparation, a high prevalence of radiographic periapical disease and unacceptable root fillings associated.

Mechanical behaviour of endodontic restorations with multiple prefabricated posts: a finite-element approach.

This paper investigates some mechanical aspects of a new endodontic restoration technique, based on the idea that the root cavity can be more efficiently filled if multiple prefabricated composite posts (PCP) are employed. Multi-post technique increases bearing capacity and durability of endodontically treated teeth, as shown by numerical simulations performed through three-dimensional elastic finite-element static analyses of a lower premolar, constrained by a non-linearly elastic spring system representing the periodontal ligament, under several parafunctional loads. The influence of PCPs' number, material and dimensions is investigated by comparison of the resulting stress fields with those obtained in cases of traditional restorations (cast metal post and cemented single-PCP) and natural tooth, highlighting the advantages of the proposed technique when standard restorative materials are considered. A risk-analysis of root-fracture and interface-failure shows that cast gold-alloy post produces high stress concentrations at post-dentin interface, whereas multi-post solution leads to a behaviour closer to the natural tooth's, exhibiting some advantages with respect to single-PCP restorations. As a matter of fact, whenever PCPs' overall cross-section area increases, multi-post solution induces a significant reduction of stress levels into the residual dentin (and therefore the root-fracture-risk decreases) as well as of the expected polymerization shrinkage effects. Moreover, interfacial stress values in multi-post restorations can be higher than the single-PCP ones when carbon-fibre posts are considered. Nevertheless, the interfacial adhesive/cohesive failure-risk is certainly acceptable if glass-fibre posts are employed.

Coverage of denuded labial bone resulting from post space preparation with a free gingival autograft: lessons learnt.

Rehabilitation of endodontically treated teeth by post and core preparation is a common procedure in day to day dental practice. However, in some instances, post space preparation can produce excessive frictional heat leading to significant damage to the attachment apparatus of the tooth as well as to the overlying soft tissue. This report describes a case of mucosal dehiscence arising due to trauma induced by inadvertent post space preparation. The denuded mucosa was restored to its physiological position with the help of free gingival autograft obtained from the palatal donor site. The aesthetic results obtained were excellent and have been stable for a period of 2 years.

Factors influencing the failure of dental glass ionomer luting cement due to contraction.

Glass ionomer cement used to fix a post within the root of a tooth undergoes cohesive failure on setting. This study aimed to determine the importance of humidity, substrate material and post design on cement failure. Nine groups of five specimens were prepared: groups 1-3 addressed the influence of post design and sectioning process on cement failure, while groups 4-9 examined the interaction between the cement, substrates and humidity. Replicas were prepared of all specimens and viewed using scanning electron microscopy. It was concluded that humidity and substrate influenced the failure of glass ionomer cement whereas post design did not.

Guidelines for the restoration of endodontically treated teeth.

Much confusion exists in the dental community regarding the restoration of endodontically treated teeth; few review articles present succinct guidelines for the restoration of these teeth. This article reviews the literature and presents guidelines for restoration of endodontically treated teeth.

A radiographic study of post-retained crowns in patients attending a dental hospital.

A total of 327 post-retained crowns were examined radiographically and a number of features were assessed including the length of post, length of remaining root filling, periapical condition, fit and angulation of the post and quality of root filling. The post length was equal to or greater than that of the crown in only 34% of cases. Although the majority of posts fitted well laterally, 43% did not extend longitudinally as far as the end of the prepared post hole. Some 20% deviated from the line of the root canal but the number of actual lateral perforations was small. A total of 47% of the teeth had areas of radiolucency around the root apices. A majority of root fillings were judged to be unsatisfactory and there was no radiographic evidence of any root filling at all in nearly 10% of cases.

The quality of impressions for crowns and bridges received at commercial dental laboratories.

OBJECTIVE: To determine the quality of impressions for crown and bridge work made in general dental practice. DESIGN AND SETTING: All impressions for crown and bridge work which had been sent to four commercial dental laboratories in the UK were assessed by two examiners, each laboratory being visited on two occasions. MATERIALS AND METHODS: 290 cases which had been received by the laboratories on the days of the visits were assessed for a number of factors related to quality. There was no selection or rejection--all impressions received were examined. RESULTS: Flexible plastic trays were used for the majority of working impressions for crown and bridge work in general dental practice (72%), many had been re-used (> 13%), defects in the recording of the prepared teeth were common, and cross infection control was not routine. CONCLUSIONS: Quality standards for impressions for crown and bridge work in general dental practice in the UK are a cause for concern if the sample of cases seen in this study is typical.

Five factors to be considered when restoring endodontically treated teeth.

UNLABELLED: Maintenance of tooth integrity and strength is critical to the longevity of any restoration. Endodontic treatment inherently requires reduction of supportive tooth structure to provide access and shape and clean the root canal system. Restorative modalities following root canal therapy must provide sufficient strength for the prosthetic material and tooth structures. This article presents several considerations in the treatment of endodontically compromised teeth to ensure clinical success. LEARNING OBJECTIVES: This article discusses relevant considerations in the restoration of endodontically treated teeth. Upon reading this article, the reader should: Understand the factors that affect the strength of an endodontically treated tooth. Recognize the available restorative options following root canal therapy.

[The clinical behavior of metal-composite post and core build-up. Results of a pilot study]. / Het klinisch gedrag van metaal-composiet stiftopbouwen. Resultaten van een pilot-studie.

During the period 1974-1986 112 post and core buildups were inserted in 74 patients. The buildups consisted of a metal prefabricated post (Dentatus, Unimetric or Radix) in combination with a composite core. After an average follow-up period of 7.9 years 14 failures (12.5%) were noticed. Eight teeth could be rerestored and six teeth had to be extracted. However, when correction was made for teeth with a bad initial prognosis and for extractions not related to the buildup restoration, eight failures remained caused by failure of the buildup (7.5%). Half of these concerned Dentatus posts.

[The restoration of endodontically treated teeth. A literature study of the mechanical behavior of post-core restorations]. / The restauratie van endodontisch behandelde elementen

Rapid developments in dental health and science have resulted in an increasing number of teeth receiving post and core restoration. The dentist can choose from a wide range of restoration-modalities. Success or failure of these restorations largely depends on their ability to meet functional demands. This article presents a review of the literature on the mechanical behaviour of post-core restorations, as it is determined by functional forces, shape of the tooth and restoration and properties of the materials the construction encorporates. Some attention is drawn to the importance of failure characteristics in view of re-restoration possibilities. As a conclusion some guide-lines for the use of post and core restorations in the general dental practice are formulated.

The role of resin cement on bond strength of glass-fiber posts luted into root canals: a systematic review and meta-analysis of in vitro studies.

Because there are several ways to cement glass-fiber posts (GFPs) into root canals, there is no consensus on the best strategy to achieve high bond strengths. A systematic review was conducted to determine if there is difference in bond strength to dentin between regular and self-adhesive resin cements and to verify the influence of several variables on the retention of GFPs. This report followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. In vitro studies that investigated the bond strength of GFPs luted with self-adhesive and regular resin cements were selected. Searches were carried out in the PubMed and Scopus databases. No publication year or language limit was used, and the last search was done in October 2012. A global comparison was performed between self-adhesive and regular resin cements. Two subgroup analyses were performed: 1) Self-adhesive × Regular resin cement + Etch-and-rinse adhesive and 2) Self-adhesive × Regular resin cement + Self-etch adhesive. The analyses were carried out using fixed-effect and random-effects models. The results showed heterogeneity in all comparisons, and higher bond strength to dentin was identified for self-adhesive cements. Although the articles included in this meta-analysis showed high heterogeneity and high risk of bias, the in vitro literature seems to suggest that use of self-adhesive resin cement could improve the retention of GFPs into root canals.