Triacrylamide-Based Adhesives Stabilize Bonds in Physiologic Conditions

In this study, an acrylamide-based adhesive was combined with a thiourethane-based composite to improve bond stability and reduce polymerization stress, respectively, of simulated composite restorations. The stability testing was conducted under physiologic conditions, combining mechanical and bacterial challenges. Urethane dimethacrylate was combined with a newly synthesized triacrylamide (TMAAEA) or HEMA (2-hydroxyethyl-methacrylate; control) to produce a 2-step total-etch adhesive system. Methacrylate-based composites (70 wt% silanized filler) were formulated, containing thiourethane oligomers at 0 (control) or 20 wt%. Standardized preparations in human third molars were restored; then, epoxy replicas were obtained from the occlusal surfaces before and after 7-d storage in water or with Streptococcus mutans biofilm, which was tested after storage in an incubator (static) or the bioreactor (mechanical challenge). Images were obtained from the replicas (scanning electron microscopy) and cross sections of the samples (confocal laser scanning microscopy) and then analyzed to obtain measurements of gap, bacterial infiltration, and demineralization. Microtensile bond strength of specimens stored in water or biofilm was assessed in 1-mm2 stick specimens. Data were analyzed with analysis of variance and Tukey’s test (α = 0.05). HEMA-based materials had greater initial gap measurements, indicating more efficient bonding for the acrylamide materials. When tested in water, the triacrylamide-based adhesive had smaller gaps in the incubator or bioreactor. In the presence of biofilm, there was less difference among materials, but the acrylamide/thiourethane combination led to statistically lower gap formation in the bioreactor. HEMA and TMAAEA-based adhesives produced statistically similar microtensile bond strengths after being stored in water for 7 d, but after the same period with biofilm-challenged specimens, the TMAAEA-based adhesives were the only ones to retain the initial bond strength values. The use of a stable multiacrylamide-based adhesive led to the preservation of the resin-dentin bonded interface after a physiologically relevant challenge. Future studies will include a multispecies biofilm model.

Sensitivity and Specificity of Different Diagnostic Methods in Occlusal Caries Detection of Permanent Teeth among Paediatric Patients

Dental caries is a commonly progressive disease that proceeds through various degrees of severity that a dentist can detect. The aims of the in vivo study were to assess the accuracy of the individual model (near-infrared light transillumination [NILT] device, visual and radiographic examinations) in detecting occlusal caries, and to evaluate the performance of visual and NILT device combination for occlusal caries detection in deciding the treatment options. Fifty-two non-cavitated occlusal surfaces from 16 patients were assessed with three different diagnostic devices in random order. Identified lesions were prepared and validated. Logistic regression analysis was performed for each method. The sensitivity and specificity values for each method and the combined models were statistically measured using RStudio version 0.97.551. At the enamel level, visual detection was the most sensitive method (0.88), while NILT was the most specific (0.93). NILT scored the highest for sensitivity (0.93) at the dentine level and visual detection scored the highest for specificity (0.88). Visual detection + NILT model was significantly better (p = 0.04) compared to visual detection or NILT alone (df = 1). The visual-NILT combination is a superior model in detecting occlusal caries on permanent teeth. The model provided surplus value in caries detection hence improving the treatment decision-making in occlusal surfaces.

Gingival hyperplasia treatment using diode laser gingivectomy in a child with cerebral palsy: case report

Gingival hyperplasia is associated with several factors, such as chronic inflammation due to the large accumulation of biofilm and medications including anticonvulsants. The aim of this study is to report a clinical case of a 4-year-old spastic quadriplegic cerebral palsy patient with gingival hyperplasia in the palatal region of the upper teeth induced by the use of high doses of anticonvulsant medications. The patient attended the Dental Assistance Center for People with Disabilities, with fibrotic gingival hyperplasia in the upper posterior region, covering the dental crowns on the palatal and occlusal surfaces. Oral hygiene instructions were previously carried out using chlorhexidine gluconate solution (0.12%) on the teeth with the aid of a cotton swab, twice a day for seven days, to reduce bacterial plaque levels and control periodontal inflammation. Gingivectomy was performed using a gallium aluminum arsenide diode laser (GaAlAs; 808±10 nm, 2.5 W output power, continuous mode). Following the surgical procedures, photobiomodulation therapy was performed with a low-level aluminum gallium indium phosphide diode laser (InGaAlP; 660±10 nm, 100 mW, 3 J) at three points (anterior, middle and posterior region of surgical wound). The patient returned at 7 and 30 days after surgery presenting accelerated wound healing. It was concluded that the high-level diode laser associated with photobiomodulation therapy were effective for performing a conservative and safe procedure in a patient with severe neurological disorder.

Effectiveness of Silver Diamine Fluoride in Preventing Occlusal Caries in Primary Teeth of Preschool Children: a Study Protocol for a Randomized Clinical Trial (Preprint)

BACKGROUND Tooth decay is a significant public health problem globally. The caries-arrest effectiveness of 38% silver diamine fluoride (SDF) has been well documented. However, information on the caries preventive effect of SDF on primary teeth is insufficient. OBJECTIVE The aim of this trial is to investigate the effectiveness of semi-annual application of 38% SDF and that of 5% sodium fluoride (NaF) varnish when compared to placebo control in preventing occlusal caries in primary molars of preschool children over 30 months. METHODS This three-arm, parallel design, double-blind, randomised controlled trial involves 791 preschool children. Children are randomly allocated to receive one of the three interventions as follows; Group 1) 38% SDF, Group 2) 5% NaF varnish, and Group 3) placebo control with tonic water. The intervention and dental examination will be carried out every 6 months. A parent-administered questionnaire including the children’s demographic background and oral health-related behaviours has been collected at baseline. Follow-up examinations to detect new caries development will be conducted every 6 months by a masked examiner. Caries development will be diagnosed at the cavitation level. Chi-square tests and logistic regression analyses will be adopted. A two-level logistic regression analysis will be performed to investigate the effects of the study interventions and other potential confounding factors on the development of occlusal caries. RESULTS Result: To date, a total of 791 children are participating in the study. CONCLUSIONS If SDF application is more effective than NaF varnish in preventing caries on occlusal surfaces of primary teeth, it can be a preferred choice for caries prevention in a kindergarten-based program. Results of this trial will provide valuable clinical evidence for the development of oral health strategies and policy on promotion of child oral health CLINICALTRIAL ClinicalTrials.gov NCT05084001

A DIFFERENTIATED APPROACH TO THE DIAGNOSIS OF OCCLUSIVE DISORDERS AT THE STAGES OF FUNCTIONAL EXAMINATION OF THE CHEWING APPARATUS

Occlusion is a harmonious interaction of the dental system in dynamics, ending with the contact of teeth in conditions of their normal or disturbed ratio. This is a complex action involving teeth, masticatory muscles, TMJ. Occlusive disorders are a reflection of the external manifestations of pathological processes of the dental system. There is no doubt that in the search for etiological factors of occlusion disorders, the problem will manifest itself in one of the parts of the chewing system. The aim of the study was to optimize the early diagnosis of occlusive disorders in young patients without violating the integrity of the dentition. Materials and methods. The study included 36 patients without a violation of the integrity of the dentition aged 18 to 25 years (15 men, 21 women), who did not complain of pain in the dental system. A comprehensive dental examination was carried out and an individual "questionnaire and patient's health card" was filled out. Computer analysis with the T-Scan III occlusiography system of the company Tekscan (USA) was used to register the nature of the closing of the dentition, the study of diagnostic models in the PROTAR evo 7 KAVO articulator, as well as the study of the registration of the difference in the biopotentials of the masticatory and temporal muscles proper in patients in the phase of relative physiological rest and with maximum jaw compression using a four-channel electromyograph Synapsis NMF Neurotech (Russia). The results showed that the prevalence of occlusive disorders in the study group is 83.3%. The abnormal position of the teeth in the dentition in combination with malocclusion anomalies, non-physiological relief of the occlusal surfaces of the teeth formed due to various factors which cause the appearance of premature contacts. This prevents the harmonious sliding movements of the lower jaw and is accompanied by articulatory changes in the entire chewing system.

The Biological Effects of Ozone Gas on Soft and Hard Dental Tissues and the Impact on Human Gingival Fibroblasts and Gingival Keratinocytes

Ozone is an allotropic form of oxygen, so in the medical field ozone therapy has special effects. Starting from the premise that bio-oxidative ozone therapy reduces the number of bacteria, in the present study two approaches were proposed: to evaluate the biological effects of ozone gas on the tooth enamel remineralization process and to demonstrate its impact on the morphology and confluence of human primary gingival cells, namely keratinocytes (PGK) and fibroblasts (HGF). The ozone produced by HealOzone was applied in vivo to 68 M1s (first permanent molars), both maxillary and mandibular, on the occlusal surfaces at pit and fissure. The molars included in the study recorded values between 13 and 24 according to the DIAGNOdent Pen 2190 scale, this being the main inclusion/exclusion criterion for the investigated molars. Because the gas can make contact with primary gingival cells during the ozonation process, both human gingival fibroblasts and keratinocytes were exposed to different doses of ozone (20 s, 40 s, 60 s), and its effects were observed with the Olympus IX73 inverted microscope. The contact of ozone with the human primary gingival cells demonstrates cell sensitivity to the action of ozone, this being higher in fibroblasts compared to keratinocytes, but it is not considered toxic because all the changes are reversible at 48 h after exposure.

Effect of Printing Layer Thickness on the Trueness and Margin Quality of 3D-Printed Interim Dental Crowns

The information in the literature on the effect of printing layer thickness on interim 3D-printed crowns is limited. In the present study, the effect of layer thickness on the trueness and margin quality of 3D-printed composite resin crowns was investigated and compared with milled crowns. The crowns were printed in 3 different layer thicknesses (20, 50, and 100 μm) by using a hybrid resin based on acrylic esters with inorganic microfillers or milled from polymethylmethacrylate (PMMA) discs and digitized with an intraoral scanner (test scans). The compare tool of the 3D analysis software was used to superimpose the test scans and the computer-aided design file by using the manual alignment tool and to virtually separate the surfaces. Deviations at different surfaces on crowns were calculated by using root mean square (RMS). Margin quality of crowns was examined under a stereomicroscope and graded. The data were evaluated with one-way ANOVA and Tukey HSD tests. The layer thickness affected the trueness and margin quality of 3D-printed interim crowns. Milled crowns had higher trueness on intaglio and intaglio occlusal surfaces than 100 μm-layer thickness crowns. Milled crowns had the highest margin quality, while 20 μm and 100 μm layer thickness printed crowns had the lowest. The quality varied depending on the location of the margin.

Comparative Evaluation of Resin Dentin Interface using Universal and Total- Etch Adhesive Systems on Sound and Eroded Dentin: In Vitro Study

Objective The study aimed to compare the resin-dentin interface of sound and eroded dentin using universal and total-etch adhesive systems. Material and Methods Forty caries-free extracted human premolars were collected, and the occlusal surfaces were ground by using slow speed diamond disc with copious water supply until a flat superficial dentin was exposed. The test group underwent erosive cycle (n = 20), and another group (n = 20) was reserved for control group. Erosive protocol consisted of immersion in 1.23% citric acid for 1 minute every 12 hours and stored in artificial saliva. Both the control and eroded teeth were further subdivided (n = 10) for composite restoration by using either self-etch or total-etch systems. Then the tooth samples were sectioned longitudinally and observed under confocal laser scanning microscope at ×10 magnification to evaluate resin tag length and hybrid layer thickness. Statistical Analysis The data obtained were analyzed by using independent t-test. Results The highest mean value of the resin tag length and thickness of hybrid layer was observed with total-etch system in sound dentin group compared with other groups (p < 0.001). Conclusion The resin-dentin interface of sound dentin was found to be better than eroded dentin by using total-etch system. The resin-dentin interface of eroded dentin was superior to sound dentin by using self-etch adhesive system.

Odontoscopic and morphometric assessment of occlusion circuits of permanent teeth in patients with physiological occlusion

A dentist needs special knowledge in odontology and odontoglyphics, which allows visualizing the space and relief of the tooth surface, as well as conducting an in-depth analysis of the individual morphometric characteristics of the tooth. Expansion of knowledge about the variability of the occlusal relief will allow achieving balanced occlusal-articulation relationships of the dentition and preserving the physiological state of the dentition. The article presents the results of odontoscopic and morphometric studies of vertical, transverse parameters of the upper large molars in patients with various physiological types of occlusion. The subject of the study was the segments of the upper molars obtained from plaster models of the jaws of 92 people with physiological occlusion, a full set of permanent teeth and various types of dental system (patients in group 1 – normodontism, patients in group 2 – macrodontism, patients in group 3 – microdontism). For morphometry in the transverse direction, the vestibular-lingual size of the crown and neck of the tooth, as well as the intertubercular distance, were used. To measure the vertical parameters, the height of the mesial (protocone, paracone) and distal (metacone, hypocone) odontomeres and tubercle of the occlusal surface was determined. The results of the study showed that in people with physiological occlusion and macrodontism of permanent teeth, vertical, transverse parameters exceed those of people with normodont and microdont types of the dental system. It is advisable to use the obtained odontometric features at the stages of diagnosing occlusal relationships and identifying various forms of pathological, physiological abrasion with varying degrees of loss of occlusal surfaces.

The Restoration of Severe Generalized Dental Erosive Wear using Direct Composite: A Case Report

Introduction: This case report describes a conservative restorative approach in the management of severe generalized tooth wear. Case report: The male, aged 57 years, was mainly concerned with the poor appearance of his teeth with short and discolored upper incisors. History revealed that he suffered from gastric reflux for 25 years, for which he was prescribed Ranitidine and was advised to self-medicate with cider vinegar. Furthermore, he divulged that he ground his teeth at night and during the day and had a high intake of carbonated cola drinks. On examination, dentine was exposed in several areas, and to a significant extent, on the incisal aspects of the lower incisors, the palatal surfaces of the upper incisors, and the occlusal surfaces of the molars. Mandibular tori were present. The primary diagnosis was erosive tooth wear with elements of attrition and abrasion. The intervention included dietary advice and restoration with direct composite resin at an increased occlusal vertical dimension of 1.5mm on the retruded axis. The patient reported no functional problems and was pleased with the aesthetic result. Conclusion: Vinegar is promoted to have health benefits, especially with respect to glucose response, but the dental implications are overlooked. This paper reviews the literature on vinegar as a medicament and considers its role as a co-factor for erosion in this case. The clinical steps used to restore the eroded dentition by direct composite are described. The use of this approach is a safe, conservative and successful treatment option without recourse to complex and biologically costly conventional alternatives. The application of direct composite in tooth wear cases meets the European consensus requirements.