The effects of Ledermix paste on discolouration of mature teeth

Endodontic and restorative management of an adult with avulsion of multiple teeth: A case report with 5 years and 9 months of follow-up

Simultaneous avulsion of four or more teeth is a rare event. This case report examines the dental care given to an adult who, during a bicycle accident, experienced the avulsion of a mandibular incisor as well as all of his maxillary incisors. In the immediate aftermath of the accident, four out of the five incisors were located, promptly collected, and stored in a tooth rescue box, all within a 20-min window. Replantation and splinting were performed on the day of the accident. Endodontic treatment involved sequential intracanal dressing with an antibiotic-corticosteroid paste followed by calcium hydroxide prior to root canal obturation. 3 months post-accident, signs of external replacement resorption (ERR) began to appear in all the replanted teeth. The gap created by the missing maxillary central incisor was managed with a three-unit fixed dental prosthesis, despite the onset of ERR in the incisors used as abutment teeth. Regular follow-ups showed a relatively slow ERR progression rate over a span of nearly 6 years. The patient expressed satisfaction with both the esthetic and functional outcomes. This case, marked by multiple avulsions, underscores the importance of immediate and appropriate intervention alongside the imperative for carefully considered long-term management strategies. Given the decelerated bone remodeling rate in adults, ERR generally progresses at a slower pace than in children. Accordingly, this case demonstrates the viability of retaining replanted teeth over the long term, even when these teeth have been subjected to nonphysiological storage for extended durations, a factor known to impede periodontal healing.

Effects of Different Light-Assisted Power Bleaching Techniques on the Penetration of Hydrogen Peroxide into the Pulp Chamber

Background: In-office bleaching is one of the most commonly used procedures for discolored tooth treatment. Although the efficacy of tooth bleaching has been investigated, depending on the applied technique and the used materials, bleaching procedures might irritate the tooth pulp and induce surface changes in enamel. The aim of this study was to evaluate the effect of four different bleaching techniques on the penetration of hydrogen peroxide (HP) into the pulp chamber. Materials and methods: Seventy-two single-rooted sound human teeth were used. The samples were prepared and evaluated in four groups. Group 1: 35% HP gel alone (HP Gel); group 2: Nd:YAG laser (0.25 W and 10 Hz with a fiber tip size of 200 μm) irradiation was added (HP Gel+laser); group 3: HP gel mixed with graphite particles (10th of millimeter in size) derived from crashed pencil lead in association with Nd:YAG laser (HP Gel+laser+graphite); and group 4: HP gel in association with light-emitting diode (LED) (litex 686, 50 Hz, 450-490 nm) (HP Gel+LED). The amount of HP penetrating into the pulp chamber was evaluated using acetate buffer and standard graphs. Data were analyzed with one-way ANOVA test, using SPSS 17. Post hoc Tukey test was used for between-group comparisons (α = 0.05). Results: Statistical analyses showed that the HP Gel+laser+graphite group had significantly higher level of HP penetration than other groups (p < 0.001). Moreover, pulp chamber penetration of HP in the HP Gel+laser group was greater than the LED and control groups (p < 0.001). The difference between control and LED groups was not significant (p = 0.99). Conclusions: Laser bleaching associated with HP Gel and graphite particles resulted in increased penetration of HP into the pulp chamber compared with the LED and control groups.

Intracoronal tooth bleaching - A review and treatment guidelines

Intracoronal bleaching is a minimally invasive procedure that was introduced into dentistry in the 19th century. The role of that procedure in enhancing the colour of teeth subjected to internal discolouration while being conservative made it extremely popular amongst dental professionals. Different materials and techniques have been utilized over the years attempting to obtain predictable long-term results while minimizing any associated risks. Contemporarily, bleaching agents are mainly based on peroxide-releasing compounds in different formulations and delivery systems. Different theories have been formulated on the bleaching mechanism of such agents, but the exact mechanism is yet to be proven. The effect of hydrogen peroxide-based bleaching agents on the organic structure of enamel and dentine has been extensively investigated to address the effects of bonding of resin-based restorative materials to hard tooth structure. Multiple case reports raised a concern about the contribution of intracoronal bleaching in developing invasive root resorption. Modification of intracoronal bleaching techniques was thus necessary to address such concerns. This review will provide a summary of the important aspects of intracoronal bleaching, focusing on how it applies to the contemporary clinical setting. © 2023 Australian Dental Association.

A critical analysis of research methods and experimental models to study tooth discolouration from endodontic materials

As a range of materials used in endodontics may cause tooth discolouration, exploration of factors responsible for the darkening of the tooth crown or root is warranted. This narrative review paper discusses the range of technical factors that apply in laboratory studies that assess endodontic discolouration. As an example of how these factors operate, particular examples relating to discolouration caused by endodontic medicaments containing tetracycline antibiotics are used. Following the PRILE 2021 guidelines approach, a summary of key variables to be addressed in the methodology for laboratory studies is presented, to inform future work.

Pharmacological Management of Acute Endodontic Pain

Pain associated with infections of the tooth pulp and periapical tissues is intense and often the most common reason for patients seeking emergency dental care. Effective management of acute dental pain requires a deep understanding of pain mechanisms, which enables accurate diagnosis and definitive treatment. While drugs are only used as an adjunct to definitive dental treatment, a thorough understanding of their mechanism of action and effectiveness enables clinicians to effectively control intra-operative and post-operative pain and prevent persistent pain. This review describes how pain is detected, processed, and perceived. It also provides information on evidence-based strategies on the use of different classes of drugs to effectively manage endodontic pain.

Spectrophotometric insights: calcium hydroxide influences tooth discolorations induced by short-term application of antibiotic/corticosteroid pastes

OBJECTIVES

This in vitro study aimed to assess the influence of a calcium hydroxide dressing regarding the relative color change (ΔE) of enamel-dentin specimens previously exposed to antibiotic/corticosteroid pastes.

MATERIALS AND METHODS

Eighty bovine enamel-dentin specimens with a cylindrical central cavity were randomly allocated to four groups: NEG (empty), POS (blood), LED (Ledermix), and ODO (Odontopaste) (n = 20 each). The materials were applied and sealed with self-adhesive resin luting material. After 3 weeks, the materials were removed and a calcium hydroxide (Ca(OH)₂) dressing was placed in all cavities. After a further 3-week storage period, the cavities were restored with resin-based composite. Spectrophotometric color measurements were taken over 6 months, and ΔE values were calculated. A Tukey's multiple comparison test was performed to assess significant differences within the treatment groups (p < 0.05).

RESULTS

Tooth discolorations were present after 3 weeks in LED (ΔE 29.14 ± 6.55) and POS (ΔE 18.05 ± 7.03); NEG and ODO remained color stable (ΔE 3.2 ± 1.36 and ΔE 2.3 ± 1.16). The 3-week Ca(OH)₂ dressing decreased discolorations of POS (ΔE 15.93 ± 6.63; p = 0.37), whereas LED showed a further significant increase (ΔE 39.55; p < 0.0001). Between the end of the Ca(OH)₂ dressing and the final restoration no significant color changes were observed in any group (p > 0.9).

CONCLUSIONS

Discolorations induced by LED progressed during the Ca(OH)₂ dressing despite careful removal of all residues.

CLINICAL RELEVANCE

Calcium hydroxide might negatively affect the discoloring potential of Ledermix. This highlights the need for direct intracanal application methods of Ledermix ensuring a material-free access cavity or alternative antibiotic/corticosteroid pastes such as Odontopaste should be used.

How standard deviation contributes to the validity of a LDF signal: a cohort study of 8 years of dental trauma

The aim of this cohort study was to document the potential of laser Doppler flowmetry (LDF) for diagnosing tooth vitality in traumatized teeth in a population of 88 referred patients with dental trauma over a period of 8 years (2011-2018). The main reason to refer was tooth discoloration (26%), and the main trauma cause was a traffic injury (35%). Taking into account that referral for LDF is best given within the week after trauma, 66% of referrals were overdue. In 73% of cases, root canal treatment could be avoided, and in 65%, the presence of a fixed orthodontic retainer showed beneficial for pulp recovery. Data of 394 teeth were collected and submitted to multilevel modelling statistics. As a general conclusion, both LDF perfusion and concentration values proved to be highly reliable in the appreciation of tooth vitality. The difference of variability of standard deviation and range of LDF measurements involving intra-subject control teeth showed statistically significant in discriminating between vital and non-vital pulps. In non-vital teeth, the diagnostic combination of LDF, sensibility tests and peri-apical X-ray is advised.

Mechanisms of Staining with Demeclocycline and Doxycycline Root Canal Medicaments

Tetracyclines are a unique class of antibiotics which also have additional effects including anti-inflammatory, anti-resorptive and substantive within the root canal. There has been a long-held view that tetracycline medicaments discolour teeth and should be avoided. The evidence base around this topic was explored, including a review of the methodology used in laboratory studies. A search of PubMed, Medline and Scopus databases was conducted to identify studies of demeclocycline and doxycycline medicaments used in root canal therapy. An analysis of the methodology used in these studies was performed to determine if these replicate current clinical practice. The related literature on mechanisms of tetracycline stability and the effects of light, oxidation, moisture and chemical interactions was examined. Studies investigating the effects of Ledermix paste on segments of bovine dentine and avulsed or reimplanted teeth as well as combinations with other antibiotics were excluded from this review. Even though demeclocycline medicament pastes were introduced in 1962, the first laboratory studies of discolouration were not done until 2000. All later studies followed a similar approach, which included exposure to sodium hypochlorite for up to 30 minutes and storage in moist conditions with 100% humidity. Staining during dark storage and enhanced staining on exposure to light were reported, indicating multiple pathways of degradation of demeclocycline and its reaction products. Light, moisture and oxidation are the key factors which drive discolouration from demeclocycline. Clinical issues from tooth staining can be prevented by removal of medicament pastes from the access cavity, and placement of a sound interim restoration. Use of a doxycycline paste obviates concerns of staining. Laboratory assessments of the potential for staining should replicate in vivo conditions.

2016 ASE undergraduate essay competition candidate information

The aim of this review is to discuss the role of medicaments and materials used in teeth undergoing root canal treatment and how they affect the overall prognosis of root canal treated teeth. Irrigants, medicaments and materials play a vital role in RCT. They reduce the overall microbial load within the root canal system, help reduce inter-appointment pain, and induce apexification during RCT of permanent teeth with immature apices. In addition, they also help create a hermetic coronal and periradicular seal to entomb any residual microorganisms within the canals and prevent future ingress of contaminants into the root canal system and subsequent reinfection. Whilst the role of various materials in RCT has been thoroughly investigated, the available literature and longitudinal clinical studies evaluating the affect of such materials on the prognosis of RCT is scarce, and requires further investigation.

Photodynamic Inactivation of Root Canal Bacteria by Light Activation through Human Dental Hard and Simulated Surrounding Tissue

Introduction: Photodynamic inactivation of bacteria (PIB) may be a supportive antimicrobial approach for use in endodontics, but sufficient activation of photosensitizers (PS) in root canals is a critical point. Therefore, aim of this study was to evaluate the ability of PS absorbing blue (TMPyP) or red light (Methylene Blue; MB) for light activation through human dental hard and simulated surrounding tissue to inactivate root canal bacteria.

Methods: A tooth model was fabricated with a human premolar and two molars in an acrylic resin bloc simulating the optical properties of a porcine jaw. The distal root canal of the first molar was enlarged to insert a glass tube (external diameter 2 mm) containing PS and stationary-phase Enterococcus faecalis. Both PS (10 μM) were irradiated for 120 s with BlueV (20 mW/cm²; λ_em = 400–460 nm) or PDT 1200L (37.8 mW/cm²; λ_em = 570–680 nm; both: Waldmann Medizintechnik), respectively. Irradiation parameters ensured identical numbers of photons absorbed by each PS. Three setups were chosen: irradiating the glass pipette only (G), the glass pipette inside the single tooth without (GT) and with (GTM) simulated surrounding tissues. Colony forming units (CFU) were evaluated. Transmission measurements of the buccal halves of hemisected mandibular first molars were performed by means of a photospectrometer.

Results: PIB with both PS led to reduction by ≥ 5 log₁₀ of E. faecalis CFU for each setup. From transmission measurements, a threshold wavelength λ_th for allowing an amount of light transmission for sufficient activation of PS was determined to be 430 nm.

Conclusion: This study can be seen as proof of principle that light activation of given intra-canal PS from outside a tooth may be possible at wavelengths ≥ 430 nm, facilitating clinical application of PIB in endodontics.

Antimicrobial Activity of Calcium Hydroxide and Betamethasone on Enterococcus faecalis; An in vitro Assessment

INTRODUCTION

Calcium hydroxide (CH) is one of the most common intracanal medications. Corticosteroids (CS) are used in endodontics because of their anti-inflammatory activity. This study aimed to evaluate the antimicrobial effect of CH+betamethasone and CH+saline against Enterococcus faecalis (E. faecalis) using agar diffusion test and measuring the microbial zone of inhibition (ZOI).

METHODS AND MATERIALS

Four plates containing Mueller-Hinton broth and E. faecalis culture media, were prepared. In each plate, 5 holes (5×3 mm) were created and a creamy mixture of CH+betamethasone was inserted into the holes (10 holes for each material). Two holes with ampicillin disks and two empty holes were used as negative and positive controls, respectively. Plates were incubated for 24 h and then the diameter of microbial ZOI was measured. The pH of each mixture was measured by pH meter. Data were analyzed using the Mann-Whitney U test.

RESULTS

The mean diameter of ZOI for CH+betamethasone and CH+saline was 3.4 and 3 mm, respectively. The difference was not significant (P=0.143). The pH was 12.5 for CH+saline and 12.3 CH+betamethasone, respectively.

CONCLUSION

The mixture of CH+betamethasone had good antimicrobial effects against E. faecalis. Further studies are needed to confirm the value of this mixture in clinical settings.

Effect of Photo-Fenton Bleaching on Tetracycline-stained Dentin in vitro

Aim

Tetracycline-stained tooth structure is difficult to bleach using nightguard tray methods. The possible benefits of in-office light-accelerated bleaching systems based on the photo-Fenton reaction are of interest as possible adjunctive treatments. This study was a proof of concept for possible benefits of this approach, using dentine slabs from human tooth roots stained in a reproducible manner with the tetracycline antibiotic demeclocycline hydrochloride.

Materials and methods

Color changes overtime in tetracycline stained roots from single rooted teeth treated using gel (Zoom! WhiteSpeed®) alone, blue LED light alone, or gel plus light in combination were tracked using standardized digital photography. Controls received no treatment. Changes in color channel data were tracked overtime, for each treatment group (N = 20 per group).

Results

Dentin was lighter after bleaching, with significant improvements in the dentin color for the blue channel (yellow shade) followed by the green channel and luminosity. The greatest changes occurred with gel activated by light (p < 0.0001), which was superior to effects seen with gel alone. Use of the light alone did not significantly alter shade.

Conclusion

This proof of concept study demonstrates that bleaching using the photo-Fenton chemistry is capable of lightening tetracycline-stained dentine. Further investigation of the use of this method for treating tetracycline-stained teeth in clinical settings appears warranted.

Clinical significance

Because tetracycline staining may respond to bleaching treatments based on the photo-Fenton reaction, systems, such as Zoom! WhiteSpeed, may have benefits as adjuncts to home bleaching for patients with tetracycline-staining.

How to cite this article

Bennett ZY, Walsh LJ. Effect of Photo- Fenton Bleaching on Tetracycline-stained Dentin in vitro. J Contemp Dent Pract 2015;16(2):126-129.

Efficacy of LED versus KTP laser activation of photodynamic bleaching of tetracycline-stained dentine

In some well-established laser applications where large spot sizes are used, an array of high-intensity light emitting diodes (LED) emitting at similar wavelength could potentially replace the laser. This situation applies for the photodynamic bleaching of stains in teeth. This study compared the relative efficacy of an array of visible green LED (535 nm ± 15 nm) with a KTP laser in photodynamic bleaching of tetracycline-stained dentine in human tooth roots. After establishing consistent staining in 96 roots using a validated method, the roots were sectioned into 2-3-mm thick horizontal slices that were treated with gels containing rhodamine B (Smartbleach® or Smartbleach® 3LT). Colour changes were tracked up to 1 month after treatment. While both systems were effective in bleaching the tetracycline-stained dentine, KTP laser activation gave greater bleaching efficacy than LED activation, enhancing the action of the gel. Use of the KTP laser would be preferable over an LED system when confronted with tetracycline staining. Use of this photodynamic bleaching method offers valuable means to reduce the severity of tetracycline staining.

Factors affecting the rate of oxidation and resultant discolouration of tetracyclines contained in endodontic medicaments and irrigants

AIM

To determine the effect of pH, oxygen levels and ions on tetracycline oxidation and resultant discolouration.

METHODOLOGY

Solutions of demeclocycline hydrochloride or doxycycline hyclate were prepared and exposed to different pH conditions, pure oxygen or carbon dioxide, ascorbic acid or various ions (from calcium chloride, calcium nitrate, strontium chloride, magnesium chloride, zinc chloride, and bismuth nitrate). Subsequently, they were exposed to intense visible blue light (470 ± 15 nm) for 24 h. Colour change was monitored using standardized digital photography. Parametric statistical analysis employing the Wilcoxon matched-pairs signed-rank test was performed to compare the mean change in different colour channels, assessing the discolouration effect of the modified conditions.

RESULTS

An acidic pH reduced discolouration, whilst alkaline pH increased it. A higher oxygen tension resulted in more discolouration, as did the presence of calcium, strontium, and bismuth ions, all of which bind to tetracyclines. Conversely, zinc and magnesium ions had a mild photoprotective effect. Ascorbic acid, an anti-oxidant, reduced the level of discolouration.

CONCLUSIONS

The tendency of these tetracyclines to undergo photo-oxidation is increased by common variables present in the clinical environment. There are potential benefits from using photoprotectors and anti-oxidants in these materials, to reduce the possibility of discolouration.

Management of the single discoloured tooth. Part 1: Aetiology, prevention and minimally invasive restorative options

The single discoloured tooth is commonly encountered in general practice. This is the first of two articles covering the broad range of management options for the single discoloured tooth. This first part outlines the common causes of discoloration and possible methods of prevention. Minimally invasive techniques are covered. Clinical procedures are outlined and clinical cases used to demonstrate outcomes that can be achieved.

CLINICAL RELEVANCE

The single discoloured tooth is a commonly encountered clinical problem in general dental practice. A wide variety of management options exist and any one in particular may be most appropriate given the clinical scenario. It is therefore essential that general dental practitioners are familiar with the range of options that exist, as well as their indications, and consider adopting minimally invasive techniques in the first instance before moving to more invasive therapies.

Discoloration of roots caused by residual endodontic intracanal medicaments

AIMS

This study examined the extent to which intervisit corticosteroid-based antibiotic pastes (CAP) medicaments contribute to staining of tooth structure after attempted removal by irrigation techniques.

METHODS

A total of 140 roots were prepared and the canals were filled with Ledermix paste (demeclocycline), Odontopaste (clindamycin), and Doxypaste (doxycycline). The pastes were removed after 2 or 4 weeks of storage in the dark using EDTA and NaOCl with either a 27-gauge-slotted needle or an EndoActivator (Dentsply). The roots were then exposed to an intense light source for 30 minutes each week and photographed after a further 1, 3, or 6 months. Digital images were standardized and data for changes in luminosity were analysed using repeated measures ANOVA and a post hoc test.

RESULTS

Removal of the medicament did not prevent later discolouration. There was no significant difference between the paste removal methods. Ledermix paste caused the greatest darkening compared to the untreated controls, for both application periods and both methods of removal. Doxypaste and Odontopaste caused less darkening than Ledermix.

CONCLUSION

Medicaments that stain teeth may continue to discolour teeth despite best attempts to remove them. This study stresses the importance of material selection and minimising contact of Ledermix within the coronal aspects of teeth.

Crown discoloration induced by endodontic sealers: spectrophotometric measurement of Commission International de I'Eclairage's L*, a*, b* chromatic parameters

Despite the improvement of endodontic materials, crown discoloration induced by root canal sealers remains a concerning clinical issue. The aim of this study is the measurement of the alterations in CIE L*, a*, b* chromatic parameters of tooth crowns after placement of commonly used and new-generation endodontic sealers in pulp chambers. Eighty intact, fully developed third mandibular molars were randomly assigned in five groups. Crowns were cross-sectioned from the root complex 1 mm below the cement-enamel junction. The internal axial walls of the pulp chambers were debrided and coated with endodontic sealers (Roth-811, AH-26, Guttaflow, Epiphany SE). The apical access was sealed with glass-ionomer cement. The control group was only debrided. Crowns were stored in individually marked vials in standard conditions (100% humidity, 37°C). The spectral reflectance lines were recorded with a UV-Vis spectrophotometer in the visual spectrum. The CIE L*a*b* parameters were obtained by a linked computer software before sealer placement (baseline), after one week, one, three, and six months, respectively. Statistical analysis was performed with two-way mixed ANOVA models. The level of statistical significance was set at p<0.05. With the exception of the control group, experimental groups presented varying chromatic alterations. Among all experimental groups, Roth-811 sealer induced the most severe alterations in CIE L*, a*, b* chromatic parameters, during all observation periods. After root canal obturation, the clinician should be aware of the presence of remaining root canal filling materials. Thorough debridement of the pulp chamber is essential for the prevention of sealer-induced discoloration.

The diagnosis and conservative treatment of a complex type 3 dens invaginatus using cone beam computed tomography (CBCT) and 3D plastic models

AIM

To investigate the use of 3D plastic models, printed from cone beam computed tomography (CBCT) data, for accurate diagnosis and conservative treatment of a complex case of dens invaginatus.

SUMMARY

A chronic apical abscess with a draining sinus tract was diagnosed during the treatment planning stage of orthodontic therapy. Radiographic examination revealed a large radiolucent area associated with an invaginated right maxillary central incisor, which was found to contain a vital pulp. The affected tooth was strategic in the dental arch. Conventional periapical radiographs provided only partial information about the invagination and its relationship with the main root canal and with the periapical tissues. A limited-volume CBCT scan of the maxilla did not show evidence of communication between the infected invagination and the pulp in the main root canal, which could explain the pulp vitality. A novel method was adopted to allow for instrumentation, disinfection and filling of the invagination, without compromising the vitality of the pulp in the complex root canal system. The CBCT data were used to produce precise 3D plastic models of the tooth. These models facilitated the treatment planning process and the trial of treatment approaches. This approach allowed the vitality of the pulp to be maintained in the complex root canal space of the main root canal whilst enabling the healing of the periapical tissues.

KEY LEARNING POINTS

Even when extensive periapical pathosis is associated with a tooth with type III dens invaginatus, pulp sensibility tests should be performed. CBCT is a diagnostic tool that may allow for the management of such teeth with complex anatomy. 3D printed plastic models may be a valuable aid in the process of assessing and planning effective treatment modalities and practicing them ex vivo before actually performing the clinical procedure. Unconventional technological approaches may be required for detailed treatment planning of complex cases of dens invaginatus.

Discolouration potential of endodontic procedures and materials: a review

Advances in endodontic materials and techniques are at the forefront of endodontic research. Despite continuous improvements, tooth discolouration, especially in anterior teeth, is considered an undesirable consequence following endodontic treatment as it creates a range of aesthetic problems. This article aims to discuss the intrinsic and internalized tooth discolouration caused by endodontic procedures, and to address the discolouration potential of materials used during root canal treatment, including root canal irrigants, intra-canal medicaments, endodontic and post-endodontic filling materials. In addition, the discolouration patterns caused by combined endodontic and nonendodontic aetiological factors are discussed. The recommended guidelines that should be followed by dental practitioners to prevent and manage tooth discolouration are also outlined.

Tooth discoloration induced by endodontic materials: a laboratory study

AIM

To investigate the discoloration potential of endodontic materials using a bovine tooth model.

METHODOLOGY

Two hundred and 10 dentine-enamel cuboid blocks (10 × 10 × 3.5 mm) were prepared out of the middle thirds of bovine tooth crowns. Standardized cavities were prepared in the walls of the pulp chamber leaving 2 mm of enamel and dentine on the labial wall of the crown. The specimens were randomly assigned to 14 groups (n = 15). Endodontic materials were placed into the cavities as follows: group A: empty, group B: blood, group C: calcium hydroxide, group D: ApexCal, group E: Ultracal XS, group F: Ledermix, group G: triple antibiotic paste (3Mix), group H: grey MTA(GMTA), group I: GMTA + blood, group J: white MTA (WMTA), group K: WMTA + blood, group L: Portland cement (PC), group M: PC + blood and group N: AH Plus. The cavities were sealed with composite and stored in water. Standardized colour measurement (VITA Easyshade compact) was performed at the following intervals: prior to (T0) and after placement of the filling (T1), 1 week (T2), 1 month (T3), 3 months (T4), 6 months (T5) and after 1 year (T6). Colour change (ΔE) values were calculated. A two-way analysis of variance was used to assess significant differences between the endodontic materials. The mean values of all groups were compared using the Tukey multiple comparison test (α = 0.05).

RESULTS

Significant differences were detected amongst the experimental groups after 12 months (P < 0.0001). The lowest colour change values were observed in the groups N (AH Plus, 3.2 ± 1.5), A (empty, 3.8 ± 1.4), L (PC, 4.1 ± 1.7), C (calcium hydroxide, 4.7 ± 1.5), E (Ultracal XS, 5.1 ± 1.9) and J (WMTA, 7.9 ± 6.7). The most discoloration was measured in groups G (3Mix, 66.2 ± 9.9) and F (Ledermix, 46.2 ± 11.6). PC showed the best colour stability amongst the Portland cement-based materials; however, when contaminated with blood (group M), a significantly higher ΔE value (13.6 ± 4.2) was detected (P = 0.032).

CONCLUSION

Materials used in endodontics may stain teeth. Therefore, the choice of material should not rely solely on biological and functional criteria, but also take aesthetic considerations into account.

The effect of calcium hydroxide on the steroid component of Ledermix and Odontopaste

AIM

To investigate the chemical interaction of calcium hydroxide with the corticosteroid triamcinolone acetonide in Ledermix Paste and in Odontopaste, a new steroid/antibiotic paste.

METHODOLOGY

Validated methods were developed to analyse the interaction of calcium hydroxide in two forms, Pulpdent Paste and calcium hydroxide powder, with triamcinolone acetonide within Odontopaste and Ledermix Paste. High-performance liquid chromatography (HPLC) was used to analyse the mixed samples of the pastes and calcium hydroxide. The concentration of triamcinolone acetonide within the pastes was determined over 0, 2, 6, 24 and 72-h time-points. All tests with the HPLC involved the testing of the standard with triplicate injections alongside the samples. All samples were tested in duplicate with each injected twice; therefore, four tests were performed for each investigation. Linearity, precision and specificity of the testing procedures and apparatus were validated. Descriptive statistics are provided.

RESULTS

In both pastes, there was a marked rapid destruction of the triamcinolone acetonide steroid upon mixing with calcium hydroxide. Odontopaste suffered a lower rate of destruction of the triamcinolone acetonide component than Ledermix Paste, but both pastes showed very similar degrees of steroid destruction after 72 h. When using calcium hydroxide powder with Ledermix Paste, the triamcinolone was destroyed entirely and immediately.

CONCLUSION

The addition of calcium hydroxide to Odontopaste or Ledermix Paste results in the rapid destruction of the steroid.

A paradigm shift in endodontic management of immature teeth: conservation of stem cells for regeneration

OBJECTIVE

This article will review the new concept of regenerative endodontics in the management of immature permanent teeth. The potential role of stem cells to regenerate immature permanent teeth after conservative treatment will be discussed.

DATA AND SOURCES

Two sets of data source are focused in this review: (i) the characterization of various dental stem cells discovered since 2000 and (ii) recent clinical case reports showing that after conservative treatment, severely infected immature teeth with periradicular periodontitis and abscess can undergo healing and apexogenesis or maturogenesis.

RESULTS

A new protocol of treating endodontically involved immature permanent teeth based on published articles to date is summarized in the review. The key procedures of the protocol are (1) minimal or no instrumentation of the canal while relying on a gentle but thorough irrigation of the canal system, (2) the disinfection is augmented with intra-canal medication of a triple-antibiotic paste between appointments, and (3) the treated tooth is sealed with mineral trioxide aggregate (MTA) and glass ionomer/resin cement at the completion of the treatment. Periodical follow-ups will take place to observe any continued maturation of the root.

CONCLUSION

While more clinical research is needed, regenerative endodontics promotes a paradigm shift in treating endodontically involved immature permanent teeth from performing apexification procedures to conserving any dental stem cells that might remain in the disinfected viable tissues to allow tissue regeneration and repair to achieve apexogenesis/maturogenesis.

Nonvital tooth bleaching: a review of the literature and clinical procedures

Tooth discoloration varies in etiology, appearance, localization, severity, and adhesion to tooth structure. It can be defined as being extrinsic or intrinsic on the basis of localization and etiology. In this review of the literature, various causes of tooth discoloration, different bleaching materials, and their applications to endodontically treated teeth have been described. In the walking bleach technique the root filling should be completed first, and a cervical seal must be established. The bleaching agent should be changed every 3-7 days. The thermocatalytic technique involves placement of a bleaching agent in the pulp chamber followed by heat application. At the end of each visit the bleaching agent is left in the tooth so that it can function as a walking bleach until the next visit. External bleaching of endodontically treated teeth with an in-office technique requires a high concentration gel. It might be a supplement to the walking bleach technique, if the results are not satisfactory after 3-4 visits. These treatments require a bonded temporary filling or a bonded resin composite to seal the access cavity. There is a deficiency of evidence-based science in the literature that addresses the prognosis of bleached nonvital teeth. Therefore, it is important to always be aware of the possible complications and risks that are associated with the different bleaching techniques.

Review of the current status of tooth whitening with the walking bleach technique

Internal bleaching procedures such as the walking bleach technique can be used for whitening of discoloured root-filled teeth. The walking bleach technique is performed by application of a paste consisting of sodium perborate-(tetrahydrate) and distilled water (3% H2O2), respectively, in the pulp chamber. Following a critical review of the scientific literature, heating of the mixture is contra-indicated as the risk of external cervical resorption and the formation of chemical radicals is increased by application of heat. An intracoronal dressing using 30% H2O2 should not be used in order to reduce the risk of inducing cervical resorption. This review provides advice based on the current literature and discusses how the walking bleach technique can lead to successful whitening of non-vital root-filled teeth without the risks of side-effects.

Periodontal response to two intracanal medicaments in replanted monkey incisors

Intracanal medicaments are recommended for use in replanted teeth to inhibit inflammatory root resorption. This study compared the effect of calcium hydroxide (Pulpdent) and a corticosteroid-antibiotic paste (Ledermix) on periodontal healing and root resorption following replantation. Incisors of eight Macaca fascicularis monkeys were extracted, stored dry for 15 min and replanted. After 11 days, root canals in two adjacent maxillary incisors were treated with one medicament and contralateral incisors with the other medicament, or left as untreated controls. Animals were sacrificed 8 weeks later and the teeth prepared for histomorphometric evaluation of periodontal ligament inflammation and root resorption. Periodontal ligament inflammation and inflammatory root resorption were markedly inhibited by both calcium hydroxide and corticosteroid-antibiotic relative to untreated controls. Replacement resorption was lowest in the corticosteroid-antibiotic group, and significantly (P<0.05) more normal periodontal ligament was present in this group (79.6%) than in calcium hydroxide and control groups (64.6% and 62.7%, respectively). Treatment with the corticosteroid-antibiotic inhibited inflammatory resorption and was slightly more effective than calcium hydroxide in producing a periodontal healing response.

The effects of Ledermix paste on discolouration of immature teeth

AIM

The aims of this study were to: (i) investigate the effects of Ledermix paste as an intracanal medicament on discolouration of immature teeth, (ii) examine whether the discolouring effects were related to the method of application, (iii) examine the effects of sunlight upon discolouration of immature teeth and (iv) compare the degree of discolouration between mature and immature teeth.

METHODOLOGY

The root canals of 45 immature extracted human teeth were prepared and filled with either Ledermix paste, calcium hydroxide [Ca(OH)2], or saline. In group 1, Ledermix paste was only placed apical to the cemento-enamel junction (CEJ) whilst in groups 2 and 3, the paste filled the entire pulp chamber and the root canals. In group 4, Ca(OH)2 paste and in group 5, saline (control) were allowed to fill the pulp chamber and the root canals. Group 3 teeth were kept in the dark and the other groups were exposed to daylight for 12 weeks.

RESULTS

After 12 weeks, sunlight exposure had caused dark grey-brown staining in the Ledermix groups but this did not occur when the teeth were kept in the dark. More severe staining was noted when Ledermix paste filled the pulp chamber than when the paste was restricted to below the CEJ and when teeth were exposed to sunlight. When compared to the results of a similar study using mature teeth, the results were similar but the immature teeth were more severely stained than the mature teeth. The Ca(OH)2 paste caused an increase in lightness and yellowness in immature teeth.

CONCLUSION

It was concluded that Ledermix paste may cause discolouration of immature teeth. Such effects can be minimized if placement of the paste is restricted to below the gingival margin. Clinicians should ensure that Ledermix paste is not left on the walls of access cavities, especially in immature teeth.