International Arab Journal of Dentistry (IAJD)

Testing the strength of thin feather-edge monolithic multilayered zirconia crowns: A pilot study with a novel acoustic test

Estelle SAAB — 2024-11-01

Intoduction: Limited research has explored the mechanical characteristics of recently introduced multilayered monolithic zirconia (MZC) crowns with feather-edge margins design. Moreover, most of the conventional techniques for evaluating the mechanical behavior of brittle dental ceramics rely on destructive tests, making it impossible to precisely evaluate real strength values due to premature crack initiation detection failure.

Objectives: The main objective of the study was to assess the load capacity of translucent multilayered monolithic zirconia crowns with feather-edge margin thicknesses of 0.4 mm and 0.5 mm. Additionally, the research introduced a novel non-destructive acoustic emission testing (AET) technique in the laboratory to identify early cracks in dental ceramics.

Methods: Forty multilayered zirconia crowns produced using computer-aided design and computer-aided manufacturing (CAD/CAM) technology were evenly divided into two groups, each with distinct feather-edge margin thicknesses: 0.5 mm (group 1) and 0.4 mm (group 2). These crowns were securely cemented onto customized polymethyl methacrylate (PMMA) dies using a universal restorative glass ionomer. Subsequently, the crowns underwent a compressive axial loading test, controlled by an innovative AET crack detection system rooted in the principles of non-destructive laboratory testing. Fractographic analysis was conducted to determine the location of crack or eventual fracture.

Results: The proportion of MZCs with a crack was statistically higher than the proportion with a fracture in the whole sample (p<0.001). In addition, the results showed that the crowns in group 1 exhibited higher loading values than those in group 2. The mean loading capacity in group was 911.2 N ± 614.7 N. Two locations of crack and fracture were registered: occlusal and marginal. No statistical association was observed between the two groups for the location of cracks or fractures.

Conclusions: The feather-edge crowns with a 0.5 mm margin thickness had a higher loading capacity than those with a 0.4 mm. However, the latter supports loads that exceed occlusal force in the oral cavity suggesting that 0.4 mm feathered edge MZCs may be a valid and less invasive alternative to thicker margins.
The novel load-to-fracture AET setup proved effective in detecting early crack initiation, suggesting it as a promising method for assessing the mechanical properties of brittle materials prior to failure, potentially impacting the field of dentistry. However more advanced research is needed to enhance the accuracy of the proposed technique.

Clinical implications: The examined MZC demonstrates the ability to withstand occlusal forces in a patient’s mouth, offering clinical practitioners the option of embracing minimally invasive dentistry through the use of 0.4 mm feather-edge MZC in their treatment options. Furthermore, the positive results from the innovative acoustic emission testing technique, facilitating early crack detection, indicate a promising future for studying the behavior of brittle materials in dental laboratory testing.

The role of neutrophils-lymphocytes ratio (NLR), lymphocytes-monocytes ratio (LMR), platelets-lymphocytes ratio (PLR) in oral cancer and acute dental infections

Sasti Priya GOVINDASAMY SUKUMAR — 2024-11-01

Objectives: The present study was a cross-sectional observational study, which was carried out on patients reported to the Department of Oral Medicine and Radiology. This study aims to evaluate the hemogram parameters NLR, LMR, and PLR among 90 Patients.

Methods: Patients were divided into 3 groups: Group A consists of 30 patients with histopathological confirmed oral cancer. Group B consists of 30 patients who presenting acute dental infections. Group C consists of 30 patients clinically healthy subjects. The hemogram parameters NLR, LMR and PLR were compared in the 3 groups and we studied their correlation to the clinical prognostic indicators like T stage, to the presence or absence of lymph node metastasis, and to differentiation of cancer. After obtaining personal informed consent, a thorough examination of the oral cavity and the lesion was conducted with an illuminated light and mouth mirror. Blood tests were performed on all the subjects before treatment. Under aseptic conditions, Venous blood (2 ml) was collected by venepuncture of the median cubital vein in the cubital fossa of the forearm using a disposable syringe with a 24-gauge needle. The withdrawn blood was transferred into an EDTA-containing test tube. Haematological parameters were analysed using an automated haematology analyzer. NLR, LMR, and PMR were calculated as the ratio of absolute peripheral neutrophil to lymphocyte, lymphocyte to monocyte, and platelet to lymphocyte count, respectively.

Results: The present study revealed that NLR is significantly elevated in oral carcinoma compared to healthy individuals, but is lesser than in patiemts with acute dental infections. LMR is higher in oral carcinoma than in acute dental infections and healthy individuals, but no statisticaly significant difference was detected among the groups. PLR is higher in oral carcinoma than in Acute dental infections and healthy individuals, and it is statistaicaly significant. There are significant correlations in oral carcinoma between NLR, LMR, and PLR. NLR has a positive correlation with PLR and a negative correlation with LMR, which showed clinical significance as determined by the Spearman correlation coefficient. In Acute dental infections and healthy individuals, there is a significant correlation of NLR with LMR and PLR but no significant correlations between LMR and PLR and vice versa. NLR, LMR, and PLR were correlated to clinical prognostic indicators like T stage, presence or absence of lymph node metastasis, and differentiation of cancer. There is no significant difference in NLR, LMR, or PLR ratios concerning Clinical T staging since the p-value is greater than 0.05 for NLR, LMR, and PLR (p= 0.072, 0.446, 0.446, respectively). A statistically significant difference is found in LMR to the clinical presence or absence of Lymph node metastasis since the p-value is less than 0.05 only for LMR (p=0.018). The mean values of LMR in N0, N1, and N2 were 9.49, 5.65, and 4.40, respectively; this implies that the mean value of LMR decreases in advanced oral carcinoma as the nodal stage increases with lymph node metastases. A statically significant difference is found in NLR (p=0.011) and PLR (p =0.013) for differentiation of tumour (p-value is less than 0.05), which implies NLR & PLR values are elevated in moderate differentiated oral carcinomas when compared to well-differentiated oral carcinoma.

Conclusions: A significant elevation exists in haematological parameters like NLR, LMR, and PLR in oral carcinoma and acute dental infections.

Comparative study of dynamic cyclic fatigue resistance of two files with different kinematics

Rahma Mohamed ABDELSHAFY — 2024-11-01

Objectives: The aim of the study was to determine the dynamic cyclic fatigue resistance (DCFR) of R-motion file and Protaper Next file (PTN) by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM).

Methods: R-motion file (25/.06), PTN file (25/.06) were used and divided into 2 groups (n = 28) according to the file type. DCFR was performed using an artificial canal. Files were allowed to work until separation. The numbers of cycles to failure (NCF) and the time to fracture (TTF) were calculated. The files were subjected to DSC and SEM.

Results: R-motion files had higher NCF and TTF compared to PTN files. SEM examination showed that all files showed ductile fracture. DSC of the R-motion file displayed Austenitic phase at body temperature) 37 ˚C) while PTN file failed to demonstrate any peaks within the applied heat range. Conclusions: R-motion files had higher CFR and TTF than PTN files.

Conclusions: R-motion files had higher CFR and TTF than PTN files.

Investigation of fracture resistance with different diameters of polyetherketoneketone posts and cores material: A pilot study

Maya KABBARA — 2024-11-01

Objectives: The primary objective of this study is to investigate the resistance to fracture of Polyetherketoneketones PEKK, used as post and core by fabrication in different diameters in the canal, and comparing the test results for each group.

Methods: Thirty extracted mandibular premolars were selected, endodontically treated and prepared to receive the post and cores milled from polyetherketoneketone disk. The specimens were randomly divided into five groups (n = 6) respectively: group 1 received pekk post with diameter = 0.70 mm, group 2 received pekk post with diameter = 0.90 mm, group 3 received pekk post with diameter = 1.10 mm, group 4 received pekk post with diameter = 1.50 mm, and group 5 received pekk post with diameter = 1.70 mm. All the posts were cemented using a self-adhesive resin cement. Fracture resistance was tested using a universal testing machine, failure patterns were then observed visually and radiographically. For the fracture resistance test, the Universal Testing machine employed the load cell of 10KN and the speed of the cross head of 1mm/min. Data was analyzed using Oneway analysis of variance (ANOVA) followed by Tukey post-hoc test in order to determine significant differences among groups and the materiality threshold was set at α = 0.05.

Results: Statistical analysis revealed that the observed differences among the five groups were not significant. None of the PEKK posts caused any fracture in the root, and this observation was visually and radiographically confirmed across all groups.

Conclusions: The dentist will be able to turn the diameter of the PEKK post and core as thin as 0.70mm till 1.70mm depending on the clinical requirement with no risk of root fracture, as specified by the guidelines of this research.

Does reduced taper canal preparation increase the load capacity of endodontically treated teeth?

Mostafa M.A. ELKHOLY — 2024-11-01

Objectives: The aim of this in-vitro study is to assess and compare the load capacity of teeth with canals prepared using progressive taper versus regressive taper.

Methods: Twenty-seven extracted mandibular molars were categorized into three equal groups. The negative control group involved teeth that were accessed and restored with composite resin without canal preparation. The regressive canal preparation group used the TruNatomy file system, while the progressive canal preparation group employed the ProTaper Gold system. Subsequently, all samples underwent loading using a universal testing machine until tooth fracture occurred. The force required to fracture each tooth was recorded in Newton.

Results: The highest value was found in samples without preparation 1009.68±57.28 N, followed by TN group 979.04±31.16 N, while the lowest value was found in PTG 966.47±17.51N. There was no significant difference between different groups (p=0.118).

Conclusions: The root canal taper did not exert a significant influence on the longevity or fracture resistance of the tooth.

Digital assessment of soft and hard tissue alterations after anterior maxillary tooth extraction

Robin JALKH — 2024-11-01

Objectives: This study aimed to assess dimensional alterations in soft and hard tissues 12 weeks post-extraction using novel computerized methods. Secondary objectives included exploring potential correlations between soft tissue changes and underlying bone variations, as well as investigating relationships between soft and hard tissue alterations and various contributing factors.

Methods: For all patients, preoperative and postoperative CBCT scans and intra-oral scans were obtained. Soft and hard tissue dimensions before extraction and at 12 weeks post-extraction were measured using 3D-slicer software. Both DICOM and STL files were superimposed, and measurements were taken at 2mm and 4mm from the facial crestal level.

Results: At twelve weeks, soft tissue thickness increased by 73.5% at 2mm and 51.2% at 4mm from the facial crestal bone. In contrast, there was a 42.5% and 33% bone resorption at 2mm and 4mm, respectively. Furthermore, the study found that smokers had a higher rate of soft tissue thickening and hard tissue resorption compared to non-smokers. The female group exhibited greater soft tissue thickening and bone resorption than the male group. Finally, the central incisor showed the highest bone loss rate, followed by the canine and the lateral incisor.

Conclusions: Three months following tooth extraction, a physiological thickening of the facial soft tissue occurs concurrently with significant bone loss beneath it.

Clinical Significance: This article’s novel digital assessment methods for evaluating soft and hard tissue alterations offer the potential to optimize treatment planning, enhancing patient outcomes and minimizing complications. By providing a comprehensive understanding of post-extraction tissue changes, it empowers clinicians to tailor treatments for individual patients, improving predictability and personalized care.

Bone to implant surface contact as a criterion for immediate implant placement with simultaneous sinus augmentation in the upper molars interradicular bone: A radiological CBCT study

Nawal BABA — 2024-11-01

Objectives: The aim of this study is to determine which type of vertical relationship (between molar apices and the sinus floor) is correlated with the most favorable bone to implant contact (BIC).

Methods: The CBCT database of the Faculty of Dental Medicine was used for datasets. For each dataset, a prosthetically-driven virtual implant placement was placed in the remaining interradicular bone. Potential BIC was measured using two different implant macrogeometries (straight and tapered).

Results: The study included 20 maxillary molars with divergent root anatomy: 90% of the molars had a type II vertical relationship with the sinus floor, while only 10% had type III. Mean pBIC surface for second molars was significantly higher for straight implants compared to tapered implants. However, no significant differences in BIC% means between straight and tapered implants for any of the comparisons was found.

Conclusions: Implant macrogeometry was found to have an impact on achieving higher pBIC values in certain situations, such as for second molars and type II relationship with the sinus floor. The study highlights the need for incorporating 3D software analysis in pre-operative surgical planning.

AI and radiologist assessments on the prevalence of TMJ osteoarthritis using radiographic images: A comparative study

Louloua Z. MOURAD — 2024-11-01

Objectives: This study aims to address the significant discomfort and functional impairment associated with temporomandibular joint osteoarthritis (TMJ OA), which negatively impacts the quality of life. It emphasizes the importance of prompt diagnosis and explores the potential of an Artificial Intelligence (AI) system to enhance TMJ OA diagnosis.

Methods: The prevalence of TMJ OA was evaluated using 3 diagnostic tools: the gold standard, the AI model, and an examiner. In total, 132 patients who performed 190 cone-beam computed tomography (CBCT) images were included.

Results: The prevalence of TMJ OA was 62.11% using the gold standard, 63.68% using the AI model, and 58.42% when assessed by the examiner. No gender variation in TMJ OA diagnosis was reported (p-value>0.05). Age variations were reported with the gold standard and the examiner diagnosis. When compared to the gold standard, the AI model had remarkable sensitivity (97.46%) and specificity (91.67%).

Conclusions: The AI model shows promise in enhancing the accuracy of TMJ OA diagnosis, offering potential benefits for early detection and improved patient outcomes.

Evaluation of fracture resistance of composite resin and glass ionomer in beveled versus non beveled class II restorations in primary molars: In vitro comparative study

Suzanne ABOU AZIZ — 2024-11-01

Introduction: The high viscosity Bulk-Fill composite (Tetric N ceram) and high viscosity glass ionomer cement (Equia Forte GIC) are the most used materials in class II cavities of primary molars. They have the advantages of being placed in a single layer of 4mm and therefore allow better ergonomics and speed of use. Until now, we find failures of restorations at the level of class II cavities of temporary teeth and many authors have tested the role of the bevel in improving the mechanical strength of restorations.

Objectives: The objectives of this study are: to test the role of the bevel in improving the fracture resistance of Bulk Fill composite restorations versus GIC of class II restorations in primary molars, and to test which material has better resistance to fracture.

Methods: One hundred temporary extracted molars are collected and randomly divided into four groups: Group I (non-beveled) and II (beveled) filled with Equia forte. Group III (non-beveled) and IV (beveled) filled with Bulk Fill Ivoclar Tetric N Ceram. The specimens were subjected to thermocycling from 5 to 55° for 10000 cycles. After artificial aging, an axial loading at a speed of 1 mm/min was applied until the specimens fractured.

Results: The statistical analysis reveals the following: an average of 442.2 N for group I and 498.80 N for group II. Thus, no statistical difference was observed between the groups restored with Equia Forte (p-value>0.05). Whereas, the resistance to fracture for groups III (901.80N) and IV (2438.33N) with a p-value<0.001 so there is significant difference between the two groups.

Conclusions: The bevel improves the fracture resistance of the BulkFilll Ivoclar restorations. Whereas, it does not influence the fracture resistance of the Equia Forte group. Bulk Fill Ivoclar Tetric N ceram has better resistance to fracture than Equia Forte GIC restorations.

Assessment and quantification of the microbial flora in the output water of two types of dental chairs: A comparative study

Khalil KHARMA — 2024-11-01

Objectives: Dental Unit Waterlines (DUWL) have shown to be a perfect host for different pathogenic microorganisms. The purpose of this study was to analyze and compare the level of bacterial contamination in the output water of 2 types of DUWL.

Methods: Dental unit water samples from the air/water syringe of the A-dec (A-dec™ Performer 200, Newberg, USA) DUWL type and KaVo (ESTETICA™ E30/E70/E80 Vision, Kavo, Biberach, Germany) type were collected and analyzed for total aerobic flora, Pseudomonas aeruginosa, faecal coliforms, total coliforms, faecal streptococci and sulfite-reducing anaerobic flora.

Results: The bacteriological analysis of water samples shows the presence of bacterial contamination at high levels exceeding the standard safety guidelines of 100 CFU/mL set up by the American Dental Association (ADA) and accepted by the Centers for Disease Control and prevention (CDC) on the heterotrophic bacterial load. The data shows no statistically significant differences for all bacteriological parameters studied between the conventional A-dec DUWL type and the KaVo type that has an automated mode of decontamination.

Conclusions: Despite all the disinfecting solutions considered to eradicate the bacterial proliferation in DUWL, the problem remains one of the greatest challenges in modern dentistry. Practitioners and medical staff should not underestimate the harmful consequences of this bacterial growth, not only on the health of their patients but also on their own health.

Clinical assessment of the abutment teeth of children undergoing space maintainer therapy: A randomised controlled trial

Ayesha S. FATHIMA — 2024-11-01

Introduction: The band and loop space maintainer are one of the most commonly used fixed space maintainers in children. However, prolonged use of appliances in the oral cavity may lead to changes in gingival health and an increased risk of caries.

Objectives: This study aims to evaluate the clinical parameters of the abutment teeth, specifically the banded teeth and the tooth to which the loop is extended.

Methods: This prospective clinical study included 35 children between the age group of 5 to 9 years. The children were examined at baseline and 6-month follow-up. The abutment teeth were evaluated on bleeding on probing, pocket depth, gingival index, and occurrence of primary/ secondary caries.

Results: There was a significant difference in the bleeding on probing, pocket depth, gingival index, and occurrence of primary/ secondary caries (p<0.05).

Conclusion: Precautions and thorough knowledge about the consequences of the delivery of appliances can prevent and overcome the causes. Oral health education and constant motivation should be provided to the children on dental hygiene and regular follow-ups to avoid any extensive invasive management.

Comparative evaluation of surface changes and bond strength of microabrasion bleached enamel before and after remineralization with nano-hydroxyapatite paste: In vitro study

Ridhi DUBE — 2024-11-01

Objectives: Comparative evaluation of surface changes and bond strength of Microabrasion Bleached enamel before and after Remineralization with Nano-hydroxyapatite paste, an In vitro study.

Methods: Enamel samples were divided into - Group I - Conventional bleaching (HB), Group II - Conventional bleaching with remineralization (HB+N-Hp), Group III - Microabrasion-assisted bleaching (M+HB), and Group IV - Microabrasion-assisted bleaching with remineralization (M+HB+N Hp). Surface roughness was measured using a profilometer. Samples were stored in artificial saliva for two weeks, then bonded with nanofilled composite resin and subjected to shear bond strength (SBS) analysis.

Results: Group IV (M+HB+N-Hp) showed higher surface roughness than Groups I (HB) and II (HB+N-Hp), while Group II had significantly lower surface roughness compared to Groups III (M+HB) and IV. In terms of shear bond strength (SBS), Group III exhibited significantly higher SBS than Group I, whereas Group II showed significantly reduced SBS compared to Group I. All values were statistically significant.

Conclusions: Remineralization with N-Hp reduces the surface roughness caused by bleaching and microabrasion, potentially decreasing bacterial biofilm adherence. Despite increased surface roughness correlating with better bond strength, microabrasion-assisted bleaching followed by remineralization and direct composite veneering after two weeks is a promising minimally invasive treatment for severe tooth discolorations. Further studies should explore varying frequencies and concentrations of N-Hp application.

A comparison between the flexural strength of milled, conventional, and carbon fiber PMMA for interim implant supported fixed complete dentures: An In vitro study

Jenny ABOU NADER — 2024-11-01

Objectives: to investigate the flexural strength of three materials commonly used for interim implant-supported fixed complete dentures (ISFCDs): conventional heat cure PMMA, CAD/CAM milled PMMA, and carbon fiber-reinforced PMMA.

Methods: Sixty specimens (n=60) divided equally into three groups (heat cure, milled, carbon fiber) were prepared. Samples were inspected to ensure absence of voids or irregularities and when required, minor adjustments were made to adjust the dimensions. The samples underwent thermocycling (5-55°C for 2500 cycles) and were then tested using a three-point bend test.

Results: There was a statistically significant difference between heat cure PMMA and carbon fiber PMMA (p<0.001), between CAD-CAM resin and carbon fiber resin (p<0.001). There was no significant difference between CAD-CAM and conventional PMMA resin (p>0.05).

Conclusions: as clinical implications, using carbon fiber is a viable treatment option for interim ISFCDs. Veneering the material with pink and white resin would improve the overall esthetics.

Aesthetic rehabilitation of a complex crown-root fracture by fragment reattachment with a fiber-reinforced post: A case report

Sarra SAIDI — 2024-11-01

Complex crown-root fractures are characterized by the involvement of both crown and root with pulp exposure. They pose aesthetic, functional, and psychological problems for the patient. Furthermore, they can pose technical difficulties for the practitioner. The purpose of this case report is to describe the management of a complex crown-root fracture of the right upper central incisor with subgingival limit by reattaching the tooth fragment with fiber-reinforced post. We considered a coronal elongation (gingivectomy and osteoplasty) to recreate the biological space and to expose the limit of the fracture line to guarantee the quality of the bond.

Diagnosis and endodontic treatment of odontogenic cutaneous sinus tracts: A report of two cases

Mayada JEMÂA — 2024-11-01

Introduction: The odontogenic cutaneous sinus tract (OCST), caused by pulp necrosis, creates connections between pathological spaces and anatomical structures. Extraoral manifestations pose diagnostic challenges leading to inappropriate treatments such as multiple surgery and antibiotic therapies. Effective management requires the treatment of dental pathology through endodontic therapy or extraction. This paper presents two cases of OCST and emphasizes the importance of accurate diagnosis and successful non-surgical endodontic treatment.

Observations: Case report 1: A 23-year-old male patient referred by his dermatologist with a cutaneous sinus tract on his chin that had appeared five years ago. During this period, he reported spontaneous pain and pus discharge from the chin area. The examination revealed a periapical lesion associated with tooth number 31. Cone beam computed tomography (CBCT) revealed the existence of a localized perforation on the buccal alveolar table and a second root canal of the tooth. After six months of follow-up, the cutaneous sinus tract was significantly improved by the appropriate endodontic treatment.
Case report 2: A 36-year-old female patient was referred by her dentist to examine a chin lesion that had appeared a month ago. In clinical examination and radiographic assessment, periapical lesion associated with two mandibular central incisor teeth #41 and #31 was observed. After identifying the source of infection, endodontic treatment was carried out, and a good improvement in fistula was observed after one month.

Conclusions: The correct diagnosis and treatment of OCST are important for healing. CBCT aids to identify odontogenic origin of the sinus tract through the detection of apical periodontitis and bone lesion. Root canal therapy is the treatment of choice for these cases and should always be attempted first. Monitoring the patients is necessary until complete healing of the disease.

Clinical management of mandibular permanent premolars with periapical lesion and bilateral supernumerary teeth: A 7-years follow-up case report

Chiara PIRANI — 2024-11-01

Objectifs: This 7-years follow-up case report describes two diversified strategies for the management of bilateral mandibular permanent premolars associated with periapical lesion and unerupted supernumerary teeth.

Case Report: A non-syndromic 9 years-old Asian female patient presented pain and swelling of the 35 in anatomical contiguity with an immature and unerupted supernumerary tooth. Clinical examination revealed an intraoral vestibular sinus tract related to the necrotic 35. Periapical radiography and CBCT showed that the 35 had an immature apex associated with a periapical lesion, and a supernumerary tooth in a lingual direction. Endodontic treatment of the 35 was performed by creating an apical plug with ProRoot MTA, while the supernumerary tooth was monitored radiographically with no intervention. Four years later, the 45 developed the same clinical condition of the left arch. Radiographic examination revealed a periapical lesion with massive periapical bone resorption, and a supernumerary tooth in normal alignment. The second premolar was herein extracted to allow for eruption of the supernumerary tooth.

Outcomes: 3-years follow-up revealed continued root maturation and its spontaneous eruption in the dental arch. Proper healing of both mandibular lesions was monitored after 10 months, 3-years and 7-years revealing no recurrence on both sides.

Endocrown, from preparation to bonding: Case report

Amira YOUSFI — 2024-11-01

The restoration of endodontically treated teeth is a real challenge, particularly teeth with extensively damaged coronal tissues. The use of post-retained restorations has been discussed because of the potential tooth weakening due to the additional removal of sound dental structures. In fact, long-term prognosis of a devitalized tooth is closely related to the coronal restoration’s quality and the remaining dental structure.
With the development of adhesive dentistry and minimally invasive preparation, new approaches have emerged. Among them, the endocrown which is monolithic ceramic bonded restoration, anchored to the internal portion of pulp chamber and cavity margins that have been used as an alternative to conventional post and core.

Does the application of polywave light-curing units influence physico-mechanical properties of resin-based materials? A meta-analysis of In vitro studies

Miguel Ángel FERNÁNDEZ-BARRERA — 2024-11-01

The objective of this study was to systematically review the existing literature and to assess the effect of the use of polywave light-curing units on the properties of resin-based materials. A thorough search was conducted across five electronic databases: PubMed (MedLine), ISI Web of Science, SciELO, Scopus, and EMBASE.
Inclusion criteria comprised in-vitro studies that compared the effects of polywave light-emitting diode (LED) curing units with monowave LED curing units on resin-based material properties. Two reviewers evaluated the methodological quality of the included studies, considering parameters from previous systematic reviews.
Meta-analyses were conducted using Review Manager version 5.3.5 (The Cochrane Collaboration, Copenhagen, Denmark). Overall, when the TPO photoinitiator was employed, the use of a polywave light-curing unit demonstrated statistically significant higher values solely for the degree of conversion (p<0.001) and hardness (p<0.01).
No statistically significant differences were observed between monowave and polywave light curing units in the other evaluated properties.
Based on the findings of this review, the use of polywave light-curing can be useful for polymerizing materials that contain photoinitiators other than camphorquinone in their composition.

Assessment of clinical performance of universal adhesives versus other adhesive systems: A systematic review and meta-analysis of clinical trials

Rim BOURGI — 2024-11-01

Universal adhesives (UAs) often exhibit comparable or even superior bond strength to traditional adhesive systems, ensuring reliable and long-lasting adhesion between the resin composite and the tooth structure.
Therefore, this study aimed to assess the clinical performance of UAs compared to other adhesive systems in direct resin composite restorations through a systematic review and meta-analysis. Two reviewers executed a literature search in five electronic databases: PubMed, EMBASE, Scopus, Web of Science, and Scielo. Clinical trials comparing the clinical evaluation of resin composite restorations in Class I, Class II, or Class V cavities placed with an universal adhesive (UA) system against resin composite restorations placed with another non-UA system were included in the review.
An analysis was carried out using Review Manager software version 5.3.5 (London, England, United Kingdom). Standardized effect sizes with 95% confidence intervals were calculated to allow comparisons between different interventions and different outcomes. The methodological quality of each study was assessed using the Cochrane RoB2 tool for randomized clinical trials.
A total of 2331 potentially relevant studies were identified. After title and abstract examination, 14 studies remained in the systematic review. From these, a total of 11 studies were included in the meta-analysis. The retention rates of resin composite restorations after 6 months showed no significant difference between total-etch (TE, p=0.83), or self-etch (SE, p=0.78) adhesives and UAs applied in TE and SE modes (p>0.05). However, UAs applied in selective-enamel etching (SEE) mode demonstrated superior clinical performance compared to other adhesives (p=0.01), particularly TE adhesives (p=0.02). Similarly, after >12 months of follow-up, there were no significant differences in retention rates among different adhesive modes (p>0.05). Additionally, the incidence of secondary caries did not significantly differ across adhesive modes at both 6-month and >12-month evaluations (p>0.05).
This systematic review and meta-analysis suggested that UAs demonstrate comparable clinical performance to TE and SE adhesive systems in direct resin composite restorations, particularly in terms of restoration retention rates and the incidence of secondary caries. UAs applied in SEE mode exhibited superior clinical outcomes compared to other adhesive systems. These findings indicate that UAs can be considered a viable alternative to traditional adhesive systems in clinical practice, offering flexibility in application while maintaining comparable long-term outcomes.

Maintenance of dental bleaching: A systematic review

Emma DEVOTO — 2024-11-01

After bleaching procedure, color pigments can adhere to the rough dental surface and can trigger more discoloration. In this sense, no standard post-bleaching maintenance technique exists. The purpose of this study was to evaluate the maintenance of enamel color after bleaching procedure through a systematic review.
The research question was defined as follows: Is the tooth whitening maintenance necessary after a bleaching treatment? Two reviewers conducted the literature search in PubMed (MEDLINE), Web of Science, Scopus, EMBASE, and SciELO. Both in vitro and clinical trials reporting the color change of bleached enamel after the use of a tooth whitening agent were included in the review. The risk of bias in the included manuscripts was evaluated using the RoBDEMAT tool.
A total of 11 articles were included in the qualitative analysis. Due to the lack of groups for comparison, a meta-analysis could not be conducted. The whitening maintenance procedures identified were remineralizing agents, antioxidants, over-the-counter agents, toothpaste containing Blue Covarine, casein phosphopeptide-amorphous calcium phosphate fluoride paste, 0.05% sodium fluoride mouthwash, arginine, nano-hydroxyapatite, nano-carbonate apatite, and CO2 laser.
In conclusion, tooth whitening maintenance could be achieved by using some agents. The association of these agents might be beneficial for maintaining the color of the enamel throughout 12 months following bleaching procedure.