Conservative pulp therapy in the management of reversible and irreversible pulpitis.

Conservative pulp therapy is an alternative treatment option to tooth removal and root canal treatment in the management of deep caries, traumatic pulp exposures and developmental anomalies. Pulp tissue preservation can extend the long-term survival of teeth through relatively simple restorative procedures. This article aims to update clinicians on the current state of research in materials, techniques and outcomes of vital pulp therapies and provide practical guidelines for their implementation into daily practice.

A colourimetric evaluation of the effect of bacterial contamination on teeth stained with blood in vitro: Evaluation of the efficacy of two different bleaching regimes.

BACKGROUND: Tooth discolouration could occur due to bacterial contamination in traumatized teeth. Hydrogen peroxide is the commonly used bleaching agent. However, due to concerns over safety, alternative bleaching regimes such as sodium perborate (S) and thiourea-hydrogen peroxide (T) have been investigated. METHODS: Apices resected and pulp extirpated 99 premolars were divided into two groups. Group 1 and 2 was injected with blood and blood/bacteria, stored anaerobically for 35 days. The two groups were treated by bleaching with water, S or T. Teeth were rebleached after 7 days. Colourimetric evaluation was assessed using digital imaging, CasMatch standardization and CIE L*a*b colour system preoperatively, 35 days of staining and 7 and 14 of bleaching. A linear mixed model with fixed effects of time, group and bleach was used to examine colour difference. RESULTS: Blood-stained teeth were significantly redder and darker on day 35 compared with blood/bacteria-stained teeth. After bleaching, blood-stained teeth retained significant redness compared with blood/bacteria-stained teeth using either S or T. T produced a significantly whiter shade in both the groups after 14 days. CONCLUSIONS: Blood-stained teeth were significantly darker and red compared with blood/bacteria-stained teeth. T bleaching regime was more effective than S.

Investigation of the effect of rapid and slow external pH increases on Enterococcus faecalis biofilm grown on dentine.

BACKGROUND: Calcium hydroxide is a common endodontic medicament and has an antimicrobial effect by increasing the localized pH within the root canal. However, Enterococcus faecalis has shown some resistance to calcium hydroxide. METHODS: A flow cell apparatus was used to grow an E. faecalis biofilm on dentine discs. Following 4 weeks growth in Todd Hewitt Broth, flow cells were exposed to either a rapid or slow increase to pH 11.5 or 12.5. Cellular viability was determined using serial plating and the number of colony-forming units was normalized against the cellular protein content. Scanning electron microscopy was carried out to qualitatively observe the effects of the different rates of pH increase. RESULTS: A significant difference in viability between the pH rapid and slow groups was not shown in this study. Compared with pH 11.5 solutions, pH 12.5 solutions were more effective at killing bacteria although some E. faecalis still survived. CONCLUSIONS: Enterococcus faecalis did not adapt and develop a greater resistance to high pH following a slow rise in pH compared with a rapid rise in pH. As expected, pH 12.5 was more effective in reducing bacterial numbers compared with pH 11.5 although E. faecalis was not completely eliminated.

Comparative efficacy of endodontic medicaments and sodium hypochlorite against Enterococcus faecalis biofilms.

BACKGROUND: Many studies have investigated the effectiveness of root canal irrigants and medicaments against Enterococcus faecalis. The aim of this study was to compare the efficacy of commonly used medicaments against E. faecalis cultured as a biofilm on dentine substrate. METHODS: An E. faecalis biofilm was established on human dentine slices using a continuous flow cell. Each test medicament (Ledermix, Ca(OH)2 , Odontopaste, 0.2% chlorhexidine and 50:50 combinations of Ledermix/Ca(OH)2 and Odontopaste/Ca(OH)2 ) was introduced into the flow cell and biofilms were harvested and quantitated by determining cellular protein. Cellular viability was determined using serial plating and the number of colony-forming units was normalized against cellular protein to allow treatment protocols to be compared. Qualitative scanning electron microscopy analyses of the biofilm were performed after a 48-h exposure to each test agent. RESULTS: Sodium hypochlorite achieved total bacterial elimination. Ledermix and Odontopaste had no significant effect on the E. faecalis biofilm. Ca(OH)2 and 50:50 combinations of Ca(OH)2 /Ledermix or Ca(OH)2 /Odontopaste reduced the viability by more than 99% while 0.2% chlorhexidine reduced bacterial numbers by 97%. CONCLUSIONS: Sodium hypochlorite remains the gold standard for bacterial elimination in root canal therapy. However, Ca(OH)2 in isolation and combined with Ledermix, and Odontopaste was highly effective in reducing bacterial viability.

Endodontic regeneration and tooth revitalization in immature infected sheep teeth.

AIM: To examine the response of immature sheep teeth with infected root canal systems to a commonly used pulp regeneration/revitalization protocol. METHODOLOGY: Immature mandibular right first incisors in four sheep were mechanically exposed and the pulps infected. The mandibular left first incisors remained intact as controls. Five weeks later, the experimental root canals were chemo-mechanically cleaned and dressed with a triple-antibiotic paste for 4 weeks, before bleeding was induced inside the canal by mechanically irritating the periapical tissues. A collagen dressing was packed coronally onto the blood clot and the canal orifice sealed with mineral trioxide aggregate and glass ionomer cement. Six months later, the mandibles were collected and the teeth with associated periapical tissues were analysed radiographically, with CT scanning, and by histology. The changes in root length, dentine thickness in the apical third (mesially and distally), and apical diameter were analysed using Student's t-test. RESULTS: Radiographs revealed significant increases in root length, root wall thickness and narrowing of the apical diameter of the canals after treatment (P < 0.05), with no significant differences in root diameters found between the experimental and the control teeth (P > 0.05) on both radiographic and CT results. Root maturation and thickening of the walls due to hard tissue deposition was confirmed by histology in all experimental teeth. Hard tissues in the apical portion of the root were more developed than in the coronal portion. CONCLUSION: Endodontic regeneration and tooth revitalization procedures in immature infected sheep teeth showed positive outcomes with similar increases in root length and development to the control teeth.

Platelet rich plasma and dentine effect on sheep dental pulp cells regeneration/revitalization ability (in vitro).

BACKGROUND: Platelet rich plasma (PRP) has been proposed as a scaffold for pulp regeneration/revitalization instead of a blood clot. The aim of the following in vitro study was to evaluate the effect of PRP scaffold on proliferation, migration and differentiation of cultured ovine (sheep) dental pulp cells (ODPC) in the presence of dentine . METHODS: PRP was prepared by centrifuging blood at 140 g for 12 min. ODPC were cultured on PRP or platelet poor plasma (PPP) scaffolds with and without dentine discs. Cell proliferation, migration and differentiation rates were assessed. RESULTS: ODPC cultured on PRP scaffold showed significantly greater proliferation rates, migration and mineralization compared with cells on PPP or without a scaffold. Dentine discs reduced the proliferation and mineralization potential of the cells. CONCLUSIONS: A PRP scaffold has a positive effect on the proliferation, migration and differentiation of ODPC; however, dentine discs have an adverse effect on the activity of ODPC.

Efficacy of low concentrations of sodium hypochlorite and low-powered Er,Cr:YSGG laser activated irrigation against an Enterococcus faecalis biofilm.

AIM: To establish the antibacterial efficacy of low concentrations of sodium hypochlorite with and without Er,Cr:YSGG laser activation on Enterococcus faecalis biofilms in extracted teeth. METHODOLOGY: The root canals of 96 decoronated single-rooted extracted human teeth were prepared to a size 40, 0.06 taper 1 mm beyond the apex. They were mounted within a flow cell, which was sterilized before pumping a nutrient media through the root canals. The flow cell was inoculated with E. faecalis (ATCC 700802) and cultivated for 4 weeks. The root-ends were sealed, and the roots were then subjected to one of six treatment groups: group 1: syringe irrigation (SI) with saline (control) using a 27 -gauge Monoject needle 1 mm from the apex for 2 min; group 2: as for group 1 but with 1% NaOCl; group 3: as for group 1 but with 4% NaOCl; group 4: 0.5% NaOCl irrigation for 15 s followed by laser-activated irrigation (LAI) with four 15-s cycles replenishing the irrigant between cycles; group 5: as for group 4 but with 1% NaOCl as the irrigant; group 6: as for group 4 but with 4% NaOCl as the irrigant. Following treatment, teeth were crushed and viable bacteria were quantitated by serial dilution and plating. The colony-forming unit values were compared between groups using one-way anova and Tukey-adjusted post hoc tests. A two-tailed P value of <0.05 was considered statistically significant. RESULTS: The mean number of cells recovered from the 1% NaOCl SI group was significantly higher than that from the 4% NaOCl LAI group (P = 0.02). CONCLUSION: Within the limitations of this laboratory study, low-powered (0.5 W) Er,Cr:YSGG laser activation did not improve the antibacterial effect of low concentrations of sodium hypochlorite.

Clonal diversity in biofilm formation by Enterococcus faecalis in response to environmental stress associated with endodontic irrigants and medicaments.

AIM: To determine whether clonal diversity within E. faecalis affects biofilm formation when exposed to antimicrobial compounds found in endodontic medicaments and irrigants. METHODOLOGY: Five human isolates of E. faecalis were compared; biofilms were grown in microtitre trays in the presence of sodium hypochlorite, calcium hydroxide, chlorhexidine, tetracycline or clindamycin. Biofilms were quantified by staining with crystal violet and optical density determined with a microplate reader. Slime production (an amorphous extracellular matrix comprising polysaccharides, glycoproteins and glycolipids loosely attached to the cell surface) was determined qualitatively by growth on Congo red agar plates. Linear mixed models were used to examine whether medicaments affected biofilm growth of the isolates in the presence of the medicaments or irrigants. RESULTS: Overall, different endodontic antimicrobials significantly altered biofilm growth in E. faecalis isolates. Two E. faecalis isolates significantly (P < 0.0001) increased biofilm formation in the presence of tetracycline and one in the presence of NaOCl (P = 0.018). Qualitatively, slime production also varied between isolates and correlated with biofilm production. CONCLUSIONS: When subjected to sub-minimum inhibitory concentration (MIC) levels of antimicrobial compounds found in endodontic medicaments, E. faecalis isolates demonstrated significant clonal variation in their capacity to form biofilms. Interestingly, there was a correlation between slime production and the ability of isolates to form a biofilm in the presence of antimicrobials. The results indicate that isolates of E. faecalis that form biofilms in response to endodontic medicaments may be more likely to survive endodontic treatment.

Self-reported oral health of a metropolitan homeless population in Australia: comparisons with population-level data.

BACKGROUND: There is limited information on self-perceived oral health of homeless populations. This study quantified self-reported oral health among a metropolitan homeless adult population and compared against a representative sample of the metropolitan adult population obtained from the National Survey of Adult Oral Health. METHODS: A total of 248 homeless participants (age range 17-78 years, 79% male) completed a self-report questionnaire. Data for an age-matched, representative sample of metropolitan-dwelling adults were obtained from Australia's second National Survey of Adult Oral Health. Percentage responses and 95% confidence intervals were calculated, with non-overlapping 95% confidence intervals used to identify statistically significant differences between the two groups. RESULTS: Homeless adults reported poorer oral health than their age-matched general population counterparts. Twice as many homeless adults reported visiting a dentist more than a year ago and that their usual reason for dental attendance was for a dental problem. The proportion of homeless adults with a perceived need for fillings or extractions was also twice that of their age-matched general population counterparts. Three times as many homeless adults rated their oral health as 'fair' or 'poor'. CONCLUSIONS: A significantly greater proportion of homeless adults in an Australian metropolitan location reported poorer oral health compared with the general metropolitan adult population.

Comparison of MicroSeal and System B/Obtura II obturation techniques.

AIM: To compare the proportion of gutta-percha, sealer and voids following the filling of simulated root canals in plastic blocks using two warm gutta-percha techniques. METHODOLOGY: Ten simulated root canals in plastic blocks were prepared using System GT Rotary Files and a.02 taper size 40 Quantec rotary nickel-titanium instrument and then filled with MicroSeal and Kerr EWT sealer. A further 10 simulated canals were prepared solely with System GT Rotary Files and obturated with System B/Obtura II and Kerr EWT sealer. All blocks were sectioned at 1 mm intervals. The sectioned root fillings were photographed through a stereomicroscope and the resultant slides scanned. The images were analysed using adobe photoshop 6.0 to give the proportions of gutta-percha, sealer or void at each level. The data were analysed using unpaired Student's t-test and Mann-Whitney U-test. RESULTS: The MicroSeal technique produced a dense homogeneous gutta-percha fill at the apical 1 and 2 mm levels similar to the System B/Obtura II technique, but further coronally the sealer became mixed into the MicroFlow gutta-percha producing a heterogeneous mass with significantly less (P < 0.05) solid gutta-percha in the root filling compared to System B/Obtura II. The MicroSeal technique generally had more pooling of cement than the System B technique, however, this was only significantly different (P < 0.05) at the 4 mm level. The System B/Obtura II obturation gave an average of 99.27% +/- 1.09 gutta-percha fill at all levels. CONCLUSIONS: The MicroSeal technique produced a heterogeneous fill consisting of the MicroFlow Master Cone and gutta-percha from the MicroFlow Cartridge mixed with sealer. The System B/Obtura II technique produced a homogeneous fill at all levels.

Impact resistance of crowned endodontically treated central incisors with internal composite cores.

The impact fracture resistance of crowned endodontically treated teeth with composite cores but without posts, that had either no coronal dentin remaining or a 1 mm dentin collar was compared to that of unrestored caries free teeth. The teeth were struck mid-labially to simulate a common trauma situation using a pendulum device and fracture resistance determined by calculation of absorbed energies. No significant difference was found between the intact teeth and the crowned root treated teeth with composite core and a 1 mm dentin collar. Crowned root treated teeth with a composite core but no coronal dentin had significantly reduced fracture resistance (p < 0.05). Teeth with the dentin collar mainly fractured obliquely from the buccal crown margin to a point coincident with the simulated alveolus, representing a clinical situation which would allow retention rather than extraction of the tooth.

Endodontic sequelae of miniplate bone fixation.

Various techniques of rigid internal fixation have evolved to achieve skeletal stability during healing. Although the miniplates and screws currently used have many advantages, their placement and presence may present significant difficulties for clinicians subsequently providing treatment. Problems with both endodontic diagnosis and treatment after miniplate fixation are illustrated with three case reports.