Odontic periapical pressure following vital pulp extirpation

The flow behavior and sealing ability of calcium silicate root canal cement containing dimethyl sulfoxide: An in vitro study

INTRODUCTION

To develop a calcium silicate (CaSi)-based cement containing dimethyl sulfoxide (DMSO) and cement deliver device for new root canal filling technique, and to assess the flow behavior, leakage, and root canal filling quality of CaSi containing DMSO.

METHODS

CaSi containing DMSO (CSC-DMSO) and CaSi containing PEG (CSC-PEG) were prepared, and the flow characteristics of both cements were compared in gypsum and resin channels using a high-speed camera. Eight root canals were obturated by CSC-DMSO or CSC-PEG using a cement delivery device, and root canal filling quality was assessed in terms of filling length using periapical radiographs. The filling length was evaluated by 'apico-coronal extension,' measuring length in reference to apical constriction. Microleakage was measured for thirty human molars that were randomly filled with CSC-DMSO, CSC-PEG, or gutta-percha and AH plus. Preliminary obturation of CSC-DMSO with cement delivery device in human teeth was analyzed in terms of filling length and void, using periapical radiographs. Statistical analysis was performed with the Kruskal Wallis test for simulated root canal fillings and one-way ANOVA for leakage test.

RESULTS

The flow speed of CSC-DMSO reduced in gypsum channels compared to resin channels, but CSC-PEG did not exhibit significant differences in the channels. The median absolute value of apico-coronal extension was significantly lower in CSC-DMSO compared to CSC-PEG (p < 0.05). Microleakage did not statistically differ between the groups (p > 0.05). In the preliminary obturation, the mean apico-coronal extension of CSC-DMSO was -0.297 ± 0.724 mm, while CSC-PEG was not feasible due to excess apical extrusions.

CONCLUSIONS

CSC-DMSO could be considered as an alternative filling material for root canal obturation.

A critical analysis of research methods and experimental models to study irrigants and irrigation systems

Irrigation plays an essential role in root canal treatment. The purpose of this narrative review was to critically appraise the experimental methods and models used to study irrigants and irrigation systems and to provide directions for future research. Studies on the antimicrobial effect of irrigants should use mature multispecies biofilms grown on dentine or inside root canals and should combine at least two complementary evaluation methods. Dissolution of pulp tissue remnants should be examined in the presence of dentine and, preferably, inside human root canals. Micro-computed tomography is currently the method of choice for the assessment of accumulated dentine debris and their removal. A combination of experiments in transparent root canals and numerical modeling is needed to address irrigant penetration. Finally, models to evaluate irrigant extrusion through the apical foramen should simulate the periapical tissues and provide quantitative data on the amount of extruded irrigant. Mimicking the in vivo conditions as close as possible and standardization of the specimens and experimental protocols are universal requirements irrespective of the surrogate endpoint studied. Obsolete and unrealistic models must be abandoned in favour of more appropriate and valid ones that have more direct application and translation to clinical Endodontics.

Reciproc versus Twisted file for root canal filling removal: assessment of apically extruded debris

PURPOSE

The aim of this study was to evaluate the amount of apically extruded debris during endodontic retreatment with different file systems.

MATERIALS AND METHODS

Sixty extracted human mandibular premolar teeth were used in this study. Root canals of the teeth were instrumented and filled before being randomly assigned to three groups. Guttapercha was removed using the Reciproc system, the Twisted File system (TF), and Hedström-files (H-file). Apically extruded debris was collected and dried in pre-weighed Eppendorf tubes. The amount of extruded debris was assessed with an electronic balance. Data were statistically analyzed using one-way ANOVA, Kruskal-Wallis, and Mann-Whitney U tests.

RESULTS

The Reciproc and TF systems extruded significantly less debris than the H-file (p<0.05). However, no significant difference was found between the Reciproc and TF systems.

CONCLUSION

All tested file systems caused apical extrusion of debris. Both the rotary file (TF) and the reciprocating single-file (Reciproc) systems were associated with less apical extrusion compared with the H-file.

In Vitro Comparison of Apically Extruded Debris during Root Canal Preparation of Mandibular Premolars with Manual and Rotary Instruments

Background and aims. During root canal preparation, debris extruded beyond the apical foramen may result in periapical inflammation and postoperative pain. To date no root canal preparation method has been developed that extrudes no periapical debris. The purpose of this study was to identify a system leading to minimal extrusion of debris from the apical foramen. The study was conducted to comparatively evaluate the amount of apical extrusion of debris during root canal preparation using hand ProTaper and GT rotary and RaCe rotary instruments using crown-down technique.

Materials and methods. Ninety freshly extracted human single-rooted mandibular premolars were equally assigned to three groups (n=30). The root canals were instrumented using hand ProTaper, GT rotary and RaCe rotary systems. Debris and irrigant extruded from the apical foramen were collected into vials. The mean weight of the remaining debris was calculated for each group and subjected to statistical analysis.

Results. ANOVA was used to compare the mean dry weights of the debris extruded in the three groups, followedby post hoc Tukey tests for multiple comparisons the between groups. Highly significant differences were found in the amount of debris extruded among all the groups (P<0.001). The ProTaper group exhibited the highest mean debris weight (0.8293±0.05433 mg) and the RaCe system exhibited the lowest mean debris weight (0.1280±0.01606 mg).

Conclusion. All the systems tested resulted in apical extrusion of debris. However, the hand ProTaper files extruded a significantly higher amount of debris than GT and RaCe systems.

The self-adjusting file instrumentation results in less debris extrusion apically when compared to WaveOne and ProTaper NEXT

Aim:

The present ex vivo study aimed to evaluate the debris extrusion after instrumenting the root canals by three different files systems.

Materials and Methods:

Sixty extracted human mandibular premolars with single canals were selected and randomly divided into three groups (n = 20) for instrumentation with three different files. Group 1: WaveOne (primary) single reciprocating file (WO; Dentsply Maillefer, Ballaigues, Switzerland) (25/08), Group 2: Self-adjusting file (SAF; ReDent-Nova, Ra’anana, Israel) (1.5 mm), and Group 3: ProTaper NEXT X1 and X2 (PTN; Dentsply Tulsa Dental, Tulsa, OK) (25/06). Debris extruding by instrumentation were collected into pre-weighed Eppendorf tubes. These tubes were then stored in an incubator at 70°C for 5 days. The tubes were then weighed to obtain the final weight, with the extruded debris. Statistical analysis for the debris extruded apically was performed using one-way analysis of variance and post hoc Tukey's test.

Results:

The statistical analysis showed a significant difference between all the three groups tested (P < 0.01). The following post hoc Tukey's test confirmed that Group 2 (SAF) exhibited significantly least (P < 0.01) debris extrusion between the three groups tested.

Conclusions:

The SAF resulted in significantly less extrusion of debris when compared to reciprocating WO and rotary PTN.

Flare-ups in endodontics: I. Etiological factors. 1985

A number of hypothetical mechanisms which may be responsible for pain and swelling before and during endodontic therapy are presented. These mechanisms may be interrelated.

Pain in endodontics. 1986

A frequent problem in endodontics is the development of pain and swelling during or after endodontic therapy. Although the reasons for such exacerbations are not always clear, there are a number of hypotheses which will be discussed in this article.

Prophylactic use of penicillin V in teeth with necrotic pulps and asymptomatic periapical radiolucencies

As a result of (1) clinical experience with flare-ups occurring in teeth with necrotic pulps and asymptomatic periapical radiolucencies and (2) on apparent reduction to the incidence of such flare-ups by the administration of penicillin V at the first sign of swelling, this study on the prophylactic administration of penicillin V in similar cases was undertaken. The subjects were 100 consecutive clinic patients whose teeth had necrotic pulps and asymptomatic periapical radiolucencies. At the initial visit, all teeth were instrumented completely to the radiographic apex, with 0.5% to 2.54% sodium hypochlorite as the irrigant. Sterile, dry cotton pellets and ZOE restorations were used. Alternate patients were given 250 mg of penicillin V and an identical-appearing placebo with instructions to take two tablets every 6 hours for the first 24 hours, followed by one tablet every 6 hours until all tablets were taken. Pain and swelling were graded by the patients on five-point scales, and flare-ups were scored when either pain and/or swelling necessitated an unscheduled emergency visit. Fifteen patients developed flare-ups, with significantly more flare-ups in the placebo group (p less than 0.05). The findings indicate that, in selected cases, prophylactic penicillin can be used to prevent flare-ups.

Pressures created by dental injections

In routine dental practice, anesthetic solutions are injected into tissue sites of widely different distensibilities, under a variety of pressures. The purpose of the present study, during simulated dental practice, was to determine the maximum injection pressures obtained by clinicians during injections in dogs. Regular aspirating dental syringes were used together with dental anesthetic cartridges filled with isotonic saline. Maximum operator injection pressures ranged from 330 to 660 psi (17,061-34,122 mmHg). Those injection sites that were least distensible gave the highest maximum injection pressures: interosseous (21,559 mmHg); incisive papilla (18,224 mmHg); periodontal (17,630 mmHg); hard palate (11,322 mmHg); and intrapulpal (8918 mmHg). More distensible tissue sites gave much lower pressures. The data indicate that dental injection pressures vary widely from several hundred mmHg to several hundred psi, depending on the clinician's physical effort and the distensibility of the tissue.

Intracystic fluid pressure in non-keratinizing jaw cysts

The technique for registration of fluid pressure in jaw cysts by means of pressure transducer and cannulation of the cyst cavity or cementation of a two-way valve into a tooth communicating with the cyst is described. Twenty-six closed cysts were subjected to registration of intracystic pressure. Subsequent histologic examination showed that all cysts were non-keratinized. Initial pressure values in apical periodontal cysts averaged +47 mmHg, in follicular cysts +44 mmHg, and in residual cysts +38 mmHg. A median palatine cyst exhibited a pressure of +81 mmHg. Most cysts showed intracystic pulsation corresponding to the number of heart beats on electrocardiograms obtained simultaneously. The intracystic pulsation disappeared when the intracystic pressure was experimentally increased and reappeared when it was lowered. In three cases in which registration of pressure was performed 7-14 days after the aspiration of the cyst fluid, an intracystic pressure in the same range as the initial one was found. The findings indicate deficient lymphatic drainage of non-keratinizing jaw cysts.