Novel operative treatment options

Application of Selected Biomaterials and Stem Cells in the Regeneration of Hard Dental Tissue in Paediatric Dentistry-Based on the Current Literature

Currently, the development of the use of biomaterials and their application in medicine is causing rapid changes in the fields of regenerative dentistry. Each year, new research studies allow for the discovery of additional possibilities of dental tissue restoration. The structure and functions of teeth are complex. They consist of several diverse tissues that need to act together to ensure the tooth’s function and durability. The integrity of a tooth’s enamel, dentin, cementum, and pulp tissue allows for successful mastication. Biomaterials that are needed in dentistry must withstand excessive loading forces, be biocompatible with the hosts’ tissues, and stable in the oral cavity environment. Moreover, each tooth’s tissue, as well as aesthetic qualities in most cases, should closely resemble the natural dental tissues. This is why tissue regeneration in dentistry is such a challenge. This scientific research focuses on paediatric dentistry, its classification of caries, and the use of biomaterials in rebuilding hard dental tissues. There are several methods described in the study, including classical conservative methods such as caries infiltration or stainless-steel crowns. Several clinical cases are present, allowing a reader to better understand the described methods. Although the biomaterials mentioned in this work are artificial, there is currently ongoing research regarding clinical stem cell applications, which have a high potential for becoming one of the most common techniques of lost dental-tissue regeneration in the near future. The current state of stem cell development is mentioned, as well as the various methods of its possible application in dentistry.

Efficacy and Patient's Acceptance of Alternative Methods for Caries Removal-a Systematic Review

Dental caries is a disease of dental hard tissues, considered the most common non-communicable disease worldwide. Conventional treatments for caries removal are often associated with pain and fear, so different therapeutic approaches have been developed towards more conservative and pleasant treatments. This systematic review aimed to assess the efficacy and patient's acceptance of alternative methods for caries removal compared to conventional methods. The Cochrane Library, Embase, Medline/Pubmed, Web of Science, and Clinical Trials databases were searched. Clinical trials of primary dental caries treated with alternative methods were included. The last search was performed on 5 August 2020. The Population, Intervention, Comparison, and Outcome (PICO) strategy was followed. Thirty-seven clinical trials were included, reporting caries removal using alternative (chemomechanical-Brix 3000, Carie-care, Carisolv and Papacarie, laser-Er:YAG (Erbium-doped Yttrium Aluminium Garnet) and Er,Cr:YSGG (Erbium, Chromium-doped Yttrium, Scandium, Gallium and Garnet), and a system combining air and sono-abrasion-Vector^® System) and conventional methods. Alternative methods tended to prolong treatment time and lessen anesthesia need. All treatments were effective in reducing cariogenic flora, and the restoration's performance did not differ significantly. Chemomechanical solutions seemed to be the best option towards minimally invasive treatments, with good control during application and action and good treatment experiences for patients. Papacarie was demonstrated to be an effective method for caries removal with less pain, and superior acceptance by patients when compared to conventional treatments.

Comparison between conventional and chemomechanical approaches for the removal of carious dentin: an in vitro study

The present study aimed to evaluate the efficiency, effectiveness, and biocompatibility of two agents used for the chemomechanical removal of carious dentin. Sixty extracted carious human teeth were treated with a conventional bur (CBG) or chemomechanical agents – Papacarie Duo (PG) and Brix 3000 (BG). Treatment efficiency and effectiveness were assessed by the working time for carious dentin removal and Knoop microhardness values, respectively. Human pulp fibroblasts (FP6) were used to evaluate cytotoxicity by incorporating MTT dye, and genotoxicity was evaluated with the micronuclei test. The carious tissue was removed in a shorter time with CBG (median = 54.0 seconds) than the time required for chemomechanical agents (p = 0.0001). However, the time was shorter for Brix 3000 (BG) than that for Papacarie Duo (PG), showing mean values of 85.0 and 110.5 seconds, respectively. Regarding microhardness testing, all approaches tested were effective (p < 0.05). The final mean microhardness values were 48.54 ± 16.31 KHN, 43.23 ± 13.26 KHN, and 47.63 ± 22.40 KHN for PG, BG, and CBG, respectively. PG decreased cell viability compared to that of BG, but it presented no genotoxicity. Brix 3000 may be a good option for chemomechanical dentin caries removal due to its reduced removal time and lower cytotoxicity compared to the other treatment options.

The Viewpoints of Last-Year Dentistry Students of Shahid Beheshti University on the Application of Lasers as an Independent Credit in the Education of General Dentistry

Introduction: Enhancing students' pragmatic skills as an enabling means brings about changes in their curriculum, which should be reconciled with the students' educational needs. Thus, this study seeks to examine the viewpoints of last-year dentistry students on the need for the instruction of laser application as an independent credit in the general dentistry curriculum. The findings of this study can help determine the educational priorities of students while providing and compiling their curriculum. Methods: This descriptive study was done on 91 last-year dentistry students of Shahid Beheshti University in a full census manner. The data collection tool was a fieldwork questionnaire, the validity and reliability of which were evaluated. To report the findings, frequency distribution, frequency percentage, and average tableaux were utilized. Results: Amongst the 91 participants, regarding the average figures of value assignment from 1 to 10 to respond to questions, the highest value was assigned to learning the side effects of lasers (7.99 ± 0.01) and the lowest value was assigned to learning about the history of lasers and light physics (4.53 ± 0.47). Conclusion: The findings indicate that students have a positive attitude toward the incorporation of an independent laser credit in their curriculum and thus the necessity of incorporating this credit in their curriculum can be posed.

Surgical Management of Caries Lesions: Selective Removal of Carious Tissues

Traditionally, before placing a restoration, excavation of tissues affected by caries was recommended. The goal was to have all walls of the cavity on sound, hard dentin, even when at risk of pulpal exposure. Current understanding of the caries process indicates that preserving tooth structure can lead to better long-term outcomes. Selective caries excavation refers to preserving tooth structure by delineating excavation in the pulpal and axial wall according to lesion severity and depth as well as pulpal health while keeping all cavity margins on sound tooth structure. Compounding evidence indicates that when a good marginal seal is present, the lesion will arrest.

Systematic Review and Meta-Analysis of Randomized Clinical Trials on Chemomechanical Caries Removal

OBJECTIVES

The aim of this review was to assess the methodologies used in previously published prospective randomized clinical trials on chemomechanical caries removal and to conduct a meta-analysis to quantify the differences in the excavation time between chemomechanical and conventional caries removal methods.

METHODS

An electronic search was performed using Scopus, PubMed, EBSCO host, and Cochrane Library databases. The following categories were excluded during the assessment process: non-English studies published before 2000, animal studies, review articles, laboratory studies, case reports, and nonrandomized or retrospective clinical trials. The methodologies of the selected clinical trials were assessed. Furthermore, the reviewed clinical trials were subjected to meta-analysis for quantifying the differences in excavation time between the chemomechanical and the conventional caries removal techniques.

RESULTS

Only 19 randomized clinical trials fit the inclusion criteria of this systematic review. None of the 19 reviewed trials completely fulfilled Delphi's ideal criteria for quality assessment of randomized clinical trials. The meta-analysis results revealed that the shortest mean excavation time was recorded for rotary caries excavation (2.99±0.001 minutes), followed by the enzyme-based chemomechanical caries removal method (6.36±0.08 minutes) and the the hand excavation method (atraumatic restorative technique; 6.98±0.17 minutes). The longest caries excavation time was recorded for the sodium hypochlorite-based chemomechanical caries removal method (8.12±0.02 minutes).

CONCLUSIONS

It was found that none of the current reviewed trials fulfilled all the ideal requirements of clinical trials. Furthermore, the current scientific evidence shows that the sodium hypochlorite-based (Carisolv) chemomechanical caries removal method was more time consuming when compared to the enzyme-based (Papacarie) chemomechanical and the conventional caries removal methods. Further prospective randomized controlled clinical trials evaluating the long-term follow-up of papain-treated permanent teeth are needed.

Sonic and ultrasonic oscillating devices for the management of pain and dental fear in children or adolescents that require caries removal: a systematic review

OBJECTIVES

To evaluate the effectiveness and degree of acceptance by children and adolescents of the use of oscillating tips compared with rotating drills.

DESIGN

Systematic review.

DATA SOURCES

PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Library and Web of Science (October 2017).

ELIGIBILITY CRITERIA

Controlled randomised or non-randomised trials that evaluated sonic and ultrasonic oscillating devices versus rotating drill.

DATA EXTRACTION

Eligible studies were selected and data extracted independently by two reviewers. Risk of bias was assessed using the Cochrane Method.

RESULTS

Two controlled clinical trials comprising 123 children aged 2-12 years old were identified. Both trials were at high risk of selection bias and unclear risk of detection bias. In one trial, pain due to the use of oscillating drill resulted lower than employing rotating drill (Verbal Hochman Scale: RR 0.64 (95% CI 0.41 to 1.00); Visual Facial Expression Scale: RR 0.64 (95% CI 0.44 to 0.94)). In another study, compared with traditional drill ultrasonic tip was associated with a lower level of patient's discomfort (RR 0.40 (95% CI 0.20 to 0.79)) but not with dental anxiety (RR 1.29 (95% CI 0.97 to 1.71)). The effectiveness of the removal of caries as well as fillings durability were only considered in one study, but no statistically significant differences were found between the two interventions.

CONCLUSIONS

The evidence based on two low-quality studies was insufficient to conclude that the use of oscillating tips for the management of pain and dental fear in children or adolescents compared with rotating drills was more effective.

Effect of chemomechanical caries removal on bonding of resin-modified glass ionomer cement adhesives to caries-affected dentine

BACKGROUND

This study evaluated the effect of: (1) chemomechanical caries removal (CMCR); (2) dentine surface treatments and (3) dentine substrates on adhesion of resin-modified glass ionomer cement (RMGIC) adhesives.

METHODS

One hundred and twenty permanent molars exhibiting moderate cavitation on the occlusal surface into dentine were used. Seventy-five carious molars were used for bond strength testing; the remaining 45 for micromorphological evaluation of the bonded interface. Caries was excavated with NaOCl-based CMCR (Carisolv), enzyme-based CMCR (Papacarie), or conventional rotary caries removal methods. Dentine surface treatment was performed using 37% phosphoric acid, 25-30% PAA or 20% PAA + 3% AlCl3 .

RESULTS

Three-way ANOVA revealed that all three factors 'caries removal methods', 'dentine surface treatments' and 'dentine substrates' did not significantly affect bond strength (p > 0.05). Scanning electron microscopy micrographs showed that the acid-base resistant layer was thicker in caries-affected dentine compared to sound dentine.

CONCLUSIONS

NaOCl- and enzyme-based CMCR methods have no adverse effect on adhesion of RMGIC adhesives to sound and caries-affected dentine. Dentine surface treatment with 37% phosphoric acid for 5 s has no negative effect on bonding of RMGIC adhesives to dentine compared with using polyacrylic acid for 10 s. RMGIC adhesives bonded well to both sound and caries-affected dentine.

Efficacy of chemomechanical caries removal in reducing cariogenic microbiota: a randomized clinical trial

The aim of this study was to compare the efficacy of chemochemical methods (Carisolv™ and Papacárie®) versus the manual method (excavators) in reducing the cariogenic microbiota in dentine caries of primary teeth. Forty-six healthy children (5 to 9 years old) having at least one primary tooth with a cavitated dentine carious lesion were included in the study. The teeth presented no clinical or radiographic signs of pulpal involvement. The sample of 74 teeth was randomly divided into three different groups: Papacárie® (n = 25), Carisolv™ (n = 27) and Manual (n = 22). Samples of carious and sound dentine were collected with sterile excavators before and after caries removal in the three groups. The dentine samples were transferred to glass tubes containing a 1mL thioglycollate medium used as a carrier and enriched for microbiological detection of mutans streptococci and Lactobacillus spp, after incubation for 6h at room temperature. The minimum detection value for colony forming units (CFU) was 3.3 x 102 CFU/ml, and the results were converted into scores from 0 to 4. A significant difference was observed in relation to the microbiological scores before and after caries removal for all methods (Wilcoxon test; p < 0.001). The use of chemomechanical methods for caries removal did not improve the reduction of cariogenic microorganisms in dentine caries lesions, in comparison with manual excavation.

Heat generation caused by ablation of dental hard tissues with an ultrashort pulse laser (USPL) system

Heat generation during the removal of dental hard tissues may lead to a temperature increase and cause painful sensations or damage dental tissues. The aim of this study was to assess heat generation in dental hard tissues following laser ablation using an ultrashort pulse laser (USPL) system. A total of 85 specimens of dental hard tissues were used, comprising 45 specimens of human dentine evaluating a thickness of 1, 2, and 3 mm (15 samples each) and 40 specimens of human enamel with a thickness of 1 and 2 mm (20 samples each). Ablation was performed with an Nd:YVO4 laser at 1,064 nm, a pulse duration of 9 ps, and a repetition rate of 500 kHz with an average output power of 6 W. Specimens were irradiated for 0.8 s. Employing a scanner system, rectangular cavities of 1-mm edge length were generated. A temperature sensor was placed at the back of the specimens, recording the temperature during the ablation process. All measurements were made employing a heat-conductive paste without any additional cooling or spray. Heat generation during laser ablation depended on the dental hard tissue (enamel or dentine) and the thickness of the respective tissue (p < 0.05). Highest temperature increase could be observed in the 1-mm thickness group for enamel. Evaluating the 1-mm group for dentine, a significantly lower temperature increase could be measured (p < 0.05) with lowest values in the 3-mm group (p < 0.05). A time delay for temperature increase during the ablation process depending on the material thickness was observed for both hard tissues (p < 0.05). Employing the USPL system to remove dental hard tissues, heat generation has to be considered. Especially during laser ablation next to pulpal tissues, painful sensations and potential thermal injury of pulp tissue might occur.

Critical appraisal. Partial caries excavation

Regular readers will note that we depart from our normal Critical Appraisal format in this issue of the Journal. This particular Critical Appraisal resembles an expanded Contemporary Issues feature and describes a protocol for partial caries excavation that was recently implemented in the student clinics of the University of North Carolina (UNC) School of Dentistry.

Impact of interocclusal contacts on infrared laser fluorescence in pits of sound first permanent molars in children

BACKGROUND

A device based on infrared laser fluorescence (IRLF) has become available as an adjunct for the diagnosis of dental caries.

AIMS

The objective of this study was to clarify the differences of IRLF readings in the mesial, central and distal occlusal pits of first permanent molars.

DESIGN

Sixty-four children (average age 8.0 years) were examined using IRLF. The mesial, central and distal pits of clinically healthy first permanent molars were measured. The instrument provides measurements in arbitrary units on an open-ended interval scale.

RESULTS

Mean (± SE) IRLF values in the mesial pits were 4.9 ± 0.4 (upper) and 6.5 ± 0.4 (lower) and were significantly lower than those in the central (8.8 ± 0.6 and 11.5 ± 0.9) and distal (9.6 ± 0.7 and 10.4 ± 0.8) pits in the maxilla and mandible. There was no significant difference between the right (7.3 ± 0.5, 9.4 ± 0.6) and left (8.2 ± 0.5, 9.5 ± 0.6) dental arches. IRLF measurements in the mesial pits of human first permanent sound molars were lower than the central and distal pits in children whose second molars had not erupted.

CONCLUSIONS

The inherently higher IRLF values of some sites should not be misinterpreted and trigger early invasive treatment.

Heat generation caused by ablation of restorative materials with an ultrashort pulse laser (USPL) system

Heat generation during the removal of dental restorative materials may lead to a temperature increase and cause painful sensations or damage dental tissues. The aim of this study was to assess heat generation in dental restoration materials following laser ablation using an ultrashort pulse laser (USPL) system. A total of 225 specimens of phosphate cement (PC), ceramic (CE), and composite (C) were used, evaluating a thickness of 1 to 5 mm each. Ablation was performed with an Nd:YVO(4) laser at 1,064 nm, a pulse length of 8 ps, and a repetition rate of 500 kHz with a power of 6 W. Employing a scanner system, rectangular cavities of 1.5-mm edge length were generated. A temperature sensor was placed at the back of the specimens to record the temperature during the ablation process. All measurements were made employing a heat-conductive paste without any additional cooling or spray. Heat generation during laser ablation depended on the thickness of the restoration material (p < 0.05) with the highest values in the composite group (p < 0.05), showing an increase of up to 17 K. A time delay for temperature increase during the ablation process depending on the material thickness was observed in the PC and C group (p < 0.05) with highest values for cement (p < 0.05). Employing the USPL system for removal of restorative materials, heat generation has to be considered. Especially during laser ablation next to pulpal tissues, painful sensations might occur.

Removal of enamel caries with an air abrasion powder

This study compared the efficiency of air abrasion on enamel caries with selective enamel powder (SEP) or with alumina powder and a negative and positive control group. Ninety-three extracted molars with non-cavitated incipient enamel lesions were selected. After embedding the roots in resin, each lesion was sectioned perpendicular to the surface and photographed. Each lesion was classified microscopically as having or not having dentin involvement. The lesions were distributed into four groups with an equal number of enamel caries with or without dentin involvement. Each group was treated differently: Group 1 had SEP abrasion, Group 2 had alumina abrasion, Group 3 had sodium bicarbonate abrasion (negative control) and Group 4 had bur treatment (positive control). The surface was rephotographed after treatment. Superimposition of the photographs identified areas of "correct-excavation," "under-excavation" and "over-excavation." There were no statistical differences between lesions treated with or without dentin involvement for Groups 2 through 4. However, in the SEP group, all measured areas were significantly influenced by dentin involvement. In pairwise comparisons, no statistical differences were found between the alumina and bur groups. The SEP group, however, showed statistically significant differences for each area compared to the alumina group in enamel caries without dentin involvement. SEP performed as well as alumina and bur in lesions with dentin involvement. SEP is different in its ablative properties toward caries with dentin involvement or no dentin involvement. In terms of dental treatment, SEP seems to have a diagnostic potential for enamel lesions before operative intervention in patients with high caries risk.

Dental caries: A complete changeover, PART III: Changeover in the treatment decisions and treatments

Comprehensive management of dental caries should involve the management of disease as well as the lesion. Current decision making process in cariology is influenced by numerous factors such as the size/ depth/ activity of the carious lesion and age/ the caries risk status of the patient. Treatment decisions should involve planning the non-operative/ preventive treatment for non-cavitated or early cavitated lesions and also formulating operative treatment for cavitated lesions. Apart from these two responsibilities, a clinician should also be knowledgeable enough to decide when not to interfere in the caries dynamics and how frequently to recall the patient for follow-ups. The non-operative treatment prescriptions vary in dose, intensity and mode of delivery according to the caries risk status. Minimal invasion and maximal conservation of tooth structure has become the essence of current operative treatments. This part of the series elaborates on the paradigm shift in the management of dental caries.