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Bacterial decontamination of root canals can be improved by directly irradiating the dentinal walls with dental lasers or by irradiating/activating the irrigation solutions, the laser having an indirect clinical action. Inside the root canal, laser irradiation produces a thermal effect on the dentine walls and bacteria, which generates unwanted side effects, if the therapeutic protocol is not followed. The aim of this study was to evaluate the root canal walls by stereomicroscopic ex-amination, after their chemo-mechanical instrumentation and conventional laser irradiation. For this study, 35 palatal roots of upper first molars were used. For some of the palatal canals, con-ventional laser irradiation was performed using a diode laser with a wavelength of 980 nm and two different irradiation protocols. The root canal walls were examined stereomicroscopically at different degrees of magnification. The study demonstrated the effectiveness of the stereomicro-scope in examining the walls of prepared and laser irradiated root canals. Areas of morphological alteration were identified and measured on the walls of the root canals for which the irradiation protocol was not applied correctly.

Over the years, several theories regarding the etiology of bruxism have been proposed. Even though these theories are difficult to confirm or infirm, due to the controversial particularities of this disease, most of them suggest a multifactorial etiology. Many authors have emphasized the importance of separating sleep bruxism from awake bruxism, as they might have different etiologies, ending with the New Consensus which provided two different definitions for those two forms of bruxism. In 2020, experts proposed the creation of a standardized system for bruxism evaluation – STAB (Standardized Tool for the Assessment of Bruxism). According to this system, future research over bruxism will be oriented in two directions: axis A that will include studies regarding evaluation methods, and axis B that will concern studies related to etiology, risk factors and predisposing factors.

Aim of the study:The aim of this study was to highlight the histopathological lesions of the oral mucosa adjacent to acrylic removable denture. Material and methods: The histopathological study was performed on 21 fragments of human oral mucosa, collected from subjects wearing removable acrylic dentures, who presented at the Clinic of Dental Prosthetics and Oral Rehabilitation of the Faculty of Dentistry in Craiova, between January 2018 and May 2020. Results: The most common lesions in the epithelium were acanthosis, parakeratosis, associated with the presence of papillomatosis and hypertrophy of connective papillae. The lesions of the lamina propria were mostly of the chronic granulomatous inflammatory type or of the lymphoplasmocytic type, with macrophages in some places. Conclusions: The possibilities of the oral mucosa to react in the contact area with a removable partial acrylic denture are multiple, ranging from simple adaptive histopathological changes to the appearance of acute or chronic histopathological lesions.

Background and objectives: Occlusal overloads produce a series of manifestations in teeth, especially attrition and non-carious cervical lesions (NCCL). Optical Coherence Tomography (OCT) can highlight and evaluate tooth lesions. The aim of this study was to examine the changes of dental hard tissues in the cervical area because of occlusal overload by macroscopic examination and using in vitro Swept Source OCT examination. Materials and Methods: The study was performed on 21 extracted teeth with occlusal trauma. After macroscopic and OCT examination, the 2D OCT images were transformed into 3D images using ImageJ software. Statistical analysis of macroscopic and OCT images was performed with Statistical Package for Social Sciences. Results: On 21 teeth, 88 cervical lesions (cracks) were identified. Upper premolars with an occlusal Smith and Knight tooth wear score of 2 had the most NCCL. Statistical analysis revealed significant differences in the median widths of cervical lesions between teeth with score 1 and score 3. Additionally, we obtained statistically significant differences in median widths between the buccal and oral surfaces. Conclusions: These cracks can be considered precursors of NCCL. NCCL can be located on dental surfaces in the cervical area other than the buccal one. A 3D reconstruction of OCT images emphasized that cracks are located especially at enamel level, evolving towards the enamel–dentin junction, with multiple ramifications.

Developmental defects of enamel (DDEs) are deviations from the normal appearance in terms of the quantity and quality of tooth enamel. They may be genetic or acquired. The most important DDEs are hypomineralization and hypoplasia. The aim of this study was to produce “in vivo” DDE in Wistar rats by administering amoxicillin to pregnant females and to highlight these lesions after sacrifice of the pups by macroscopic and microscopic examination and optical coherence tomography (OCT). Amoxicillin (100 mg/kg) was administered to two pregnant Wistar female rats for the production of DDEs. When the pups were 2 months old, they were sacrificed, and their jaws were harvested together with their teeth. The jaws were examined macroscopically, microscopically, and by OCT. Following the macroscopic and microscopic examination, it was established that four pups had a total of 42 DDE lesions. At the OCT examination, the hypomineralization was characterized by an intense, inhomogeneous OCT signal, and the hypoplasia was characterized by the absence of the signal. Administration of amoxicillin to pregnant females of Wistar rats resulted in DDEs in their offspring. The OCT examination confirmed the presence of these lesions in the teeth of rat pups.

Non-carious cervical lesions (NCCLs) represent a form of tooth wear, characterized by the irreversible loss of dental hard tissues at the enamel–cement junction, without the involvement of caries and dental trauma. The aim of this study was to highlight the morphological elements of NCCLs via their stereomicroscopic examination and to confirm the role of this examination in the diagnosis of early lesions. In addition, the association between the morphological aspects identified during the stereomicroscopic examination of NCCLs and their etiological factors was determined. For this study, extracted teeth with NCCLs were examined with a stereomicroscope. The morphological aspects of NCCLs were evaluated at magnifications up to 75×. In wedge-shaped NCCLs, the stereomicroscopic examination allowed the identification and measurement of scratches, furrows and cracks. In saucer-shaped NCCLs, the stereomicroscopic examination highlighted the smooth appearance of the walls. The presented study highlighted the role of stereomicroscopic examination in the assessment of NCCL morphology and in their early diagnosis. The study confirmed, in particular, the role of occlusal overloads and tooth brushing in determining the morphology of NCCLs.

The success of endodontic treatment is dependent on the removal of bacteria. A modern strategy to reduce bacterial load is laser irradiation. During this procedure, there is a local increase in temperature with possible side effects. The aim of this study was to determine the thermal behavior of a maxillary first molar when performing the conventional irradiation technique using a diode laser. For this study, a 3D virtual model of a maxillary first molar was created. The preparation of the access cavity, the rotary instrumentation of the palatal root canal and the laser irradiation protocol were simulated. The model was exported in a finite element analysis program where the temperature and heat flux were studied. Temperature and heat flux maps were obtained, and the temperature increase on the internal wall of the root canal was analyzed. The maximum temperature value exceeded 400 °C and was maintained for less than 0.5 s. The obtained temperature maps support the bactericidal effect of diode laser and the limitation of damage to surrounding tissues. On internal root walls, the temperature reached several hundred degrees Celsius, but for very short durations. Conventional laser irradiation is an adjuvant method of decontamination of the endodontic system.

Aim of the study This study investigated the knowledge amongst dentists and senior dental students from Romania, regarding the clinical forms of tooth wear, its etiology and various treatment options for non-carious cervical lesions. Material and methods A questionnaire was sent electronically to Romanian dentists and dental students using social media. The survey had 16 questions regarding the prevalence of non-carious cervical lesions in the participants dental practice, the awareness of their clinical signs, etiological mechanisms and treatment options. Results Romanian dentists and dental students felt competent in diagnosing and treating tooth wear and non-carious cervical lesions, although the awareness of their etiology was moderate. For the restoration of non-carious cervical lesions, the material preferred by Romanian dentists and dental students was flowable composite. Conclusions Our study showed the need for further clinical and laboratory studies of the etiological mechanisms of tooth wear and non-carious cervical lesions for a better understanding amongst dental practitioners.

The rapid evolution of laser technology and the better understanding of laser-tissue interaction, allowed the growth of possible laser treatments, including laser assisted endodontics. Diode laser was introduced in endodontic procedures in late 1980’s and today is used for decontamination of the root canals. Lasers are used in association with various endodontic techniques, either to irradiate directly the dentinal walls, or to irradiate/activate photoactive substances/irrigants, having an indirect clinical effect on the endodontic system. Side effects resulting from irradiation with laser light do not appear if the correct parameters are used. Further clinical studies are necessary in order to evaluate the healing of endodontic diseases from laser assisted therapy.

Aim of the study This study investigated the magnitude and distribution of stress in a maxillary first premolar subjected to normal and heavy occlusal loads, that were directed vertically and horizontally, using Finite Element Analysis. Material and methods A virtual 3D model of a maxillary first premolar was created using the CT images of a 14 year-old patient and the physical and mechanical properties of the dental tissues used in other studies. We obtained 8 scenarios for the vertical loading and 8 scenarios for the horizontal loading. Results The magnitude and distribution of stress were the least favorable in the case of the heavy horizontal loading applied on the intact tooth. Conclusions Our study showed that the intact tooth was the most affected by stress regardless of the loading applied.