Vol 29, No 1 (2025)

BACKGROUND: The relationship between malocclusion and respiratory function is a pressing issue in modern orthodontics, as the position of the hyoid bone directly influences airway volume in patients with sagittal jaw relationship anomalies. Over the past decade, various authors have developed cephalometric analysis methods for assessing hyoid bone position using both lateral cephalometric radiographs and head and neck computed tomography. However, none of these methods have conclusively established an association between a distal jaw relationship and an increase in airway volume, or a mesial relationship and airway constriction. Thus, this issue remains unresolved.

AIM: To determine the impact of hyoid bone position on the airway volume in patients with sagittal jaw relationship anomalies.

MATERIALS AND METHODS: Two comparison groups were formed: the first included 74 patients with a tendency toward distal occlusion, and the second comprised 52 patients with a tendency toward mesial jaw relationship. The hyoid bone position was assessed on lateral cephalometric radiographs of patients with sagittal dentoalveolar anomalies by analyzing the GoMeH angle, formed by the tangent to the body of the mandible and the most superior and anterior point on the hyoid bone. Airway volume was analyzed using the Invivo 5 software (Anatomage, USA), based on the D.C. Hatcher color scale. Statistical analysis was performed using Statistica 13.0. Mean values were compared using Student’s t-test, and statistical significance was evaluated using a two-sample t-test and p-value.

RESULTS: A correlation was established between hyoid bone position and airway volume in patients with sagittal jaw relationship anomalies. In patients with mesial occlusion, the GoMeH angle decreased, but the airway lumen did not narrow. In patients with a distal jaw relationship, the GoMeH angle increased, but the airway volume either increased or decreased.

CONCLUSION: The position of the hyoid bone is directly linked to sagittal jaw relationship anomalies and affects airway volume. The obtained data can be applied in prosthodontic practice and orthodontic treatment planning, as well as for monitoring the treatment quality of sagittal malocclusions.

BACKGROUND: Citric acid, commonly encountered through the consumption of fruits and juices, is a frequent factor affecting teeth in daily life. It contributes to enamel dissolution, exposing the underlying dentin in the crown region and potentially leading to significant tooth surface loss. On the other hand, acid etching is widely used in restorative dentistry to enhance the adhesion of restorative materials to tooth surfaces. This process partially dissolves and demineralizes the enamel’s inorganic matrix, creating micropores and microgrooves that increase surface roughness. Pre-etching of enamel improves the bond strength of resin-based adhesives compared to non-etched enamel. Orthodontists also employ acid etching to create retention surfaces, which enhances bracket adhesion but simultaneously weakens adjacent enamel prisms, increases permeability, promotes biofilm adhesion, and reduces enamel’s protective properties.

AIM: To evaluate the effect of citric acid exposure time and etching duration on the surface properties of dental hard tissues, including enamel and dentin.

MATERIALS AND METHODS: Three enamel samples were obtained from a maxillary molar extracted from a 21-year-old male patient. The tooth was embedded in epoxy resin for easier sectioning. Sectioning parameters on the IsoMet 4000 (Buehler, Switzerland) were set to a disk rotation speed of 2500 rpm and a feed rate of 10 mm/min. Three distinct areas were selected for analysis. Each sample was embedded in epoxy resin again for subsequent grinding and polishing, which was performed simultaneously for all three samples using the MetaServ 250 (Buehler, Switzerland). The prepared enamel surfaces were examined using an optical microscope (Stemi 305; Carl Zeiss, Germany) equipped with a color video camera (Axiocam 105; Carl Zeiss, Germany) under reflected light. The samples were etched as follows: Sample 1 with 0.5 wt.% citric acid (pH = 2.3), Sample 2 with 3 wt.% citric acid (pH = 1.86), and Sample 3 with 5 wt.% citric acid (pH = 1.71). The pH was measured using Cobra4 Mobile-Link (PHYWE, Germany). Atomic force microscopy of enamel surface topography before and after etching was performed using the NANOEDUCATOR microscope (NT-MDT, Russia) with a tungsten probe operating in non-contact mode. Surface roughness (Ra) was measured at each etching stage for each sample using the Gwyddion software (Czech Metrology Institute, Czech Republic).

RESULTS: Optical microscopy provided images of enamel, dentin, and the dentinoenamel junction, confirming the healthy condition of the examined samples. The findings suggest that 5 wt.% citric acid is more suitable for controlled etching than 37% phosphoric acid, as prolonged exposure to phosphoric acid can cause severe enamel damage. AFM analysis demonstrated the surface characteristics of each sample before and after etching at different time intervals. A linear increase in surface roughness was observed in all samples after 45 s of etching.

CONCLUSION: For achieving significant surface roughness and visualizing enamel prisms within a reasonable timeframe, etching with 5 wt.% citric acid is recommended. However, further studies on the adhesive properties of enamel post-etching with citric acid are necessary for clinical implementation.

BACKGROUND: Despite extensive research on the prevention and treatment of dentoalveolar shifts in cases of dental arch defects, which develop over time, there is a lack of studies examining errors related to the displacement of prepared teeth during the laboratory fabrication of a prosthetic restoration.

With the introduction of digital technologies in clinical practice, it has become possible to assess the displacement of a prepared tooth and determine the optimal treatment duration.

CLINICAL CASE DESCRIPTION: This report presents a clinical case of prosthetic treatment in a patient diagnosed with “hard tissue defect of tooth 2.6, occlusal surface destruction index ≥ 60%,” using a digital protocol.

To analyze the extent of displacement of the prepared tooth toward the antagonists over a known period, the distance to the antagonist teeth was measured using digital models.

Digital images of the jaw models obtained immediately after tooth preparation were designated as baseline data. After 24 days, new impressions were taken, and the corresponding digital models were recorded as current data.

The digital models were superimposed in the position of centric occlusion, and the distances in the baseline and current datasets were measured ten times. To assess the displacement of the prepared tooth, the measured values were compared.

This clinical case justified the duration of prosthetic treatment considering the displacement error of the prepared tooth based on digital model comparison. Statistically significant differences were found between the measurements taken over the specified time period. The mean value of the initial measurements was 1.345 ± 0.005 mm, while the mean value of the current measurements was 1.229 ± 0.003 mm. The difference between these values indicates that the prepared tooth shifted by 0.116 ± 0.002 mm (116 ± 2 µm).

CONCLUSION: Considering the clinical findings of this study, it is recommended that fixed prosthetic treatment without the use of temporary restorations be completed within the shortest possible timeframe. The measured displacement of the prepared tooth toward the antagonist teeth, as observed on digital jaw models, indicates that laboratory fabrication of a prosthesis without a temporary restoration beyond 24 days is critical, as it leads to prosthetic misfit.

BACKGROUND: One of the key indicators of the quality of fixed prostheses is their precise fit to the prosthetic bed. Errors occurring at clinical and laboratory stages during prosthesis fabrication often lead to variations in the degree of fit of the final prosthesis. Most existing methods for evaluating prosthesis fit are primarily of scientific interest and have not gained widespread clinical application due to their complexity and inconvenience in practical use.

AIM: To improve the effectiveness of prosthetic treatment by enhancing the fit of fixed dental prostheses.

MATERIALS AND METHODS: The fit of completed prostheses was assessed using a silicone test and a specialized device — a calibrator — which enables the clinician to quickly and accurately measure the thickness of the silicone film.

RESULTS: It was found that all prostheses received from the dental laboratory exhibited varying degrees of fit. The measured values ranged from 20 to 200 µm, with 50% of the prostheses exceeding 100 µm. Adjustments made to crowns using the proposed method improved their fit by an average of 59.28%.

CONCLUSION: The proposed clinical method for assessing and correcting the marginal fit of fixed dental prostheses allows clinicians to monitor this parameter effectively and achieve clinically acceptable values.

Asthma-induced changes in the oral cavity may lead to microbial contamination, increasing the risk of dental caries, periodontal disease, and candidiasis.

This literature review examines the most relevant microorganism-associated oral diseases in asthma patients, as well as the mechanisms of their development.

The literature search and analysis were performed using international databases Google Scholar, Scopus, PubMed, Web of Science, disserCat, and eLIBRARY.RU for the period between 2004 and 2024. The following search terms were used: oral cavity, bronchial asthma, and microbes.

A total of 267 publications were identified, of which 22 were deemed relevant. Dental diseases associated with changes in the oral microecosystem (such as dental caries, gingivitis, periodontal disease, and candidiasis) and the mechanisms of their development were described based on the literature data for asthma patients. The study found that these disorders can be caused by autoimmune processes and other factors that alter oral homeostasis and activate pathogens in the oral cavity.

It was shown that changes in oral microbiota caused by microecosystem alterations contribute to the development of dental diseases, affecting both oral and general health.

BACKGROUND: Traumatic dental injuries caused by mechanical stimuli account for approximately 20% of dentofacial disorders. Dental replantation is currently viewed as a viable alternative to dental prosthetic rehabilitation and implantation. The outcome of replantation in traumatic dental injuries is largely determined by timely treatment and transportation conditions.

AIM: To perform literature search and review publications that assess and compare solutions for preserving the viability of teeth in traumatic dental injuries.

MATERIALS AND METHODS: The literature search was performed in PubMed and eLIBRARY.RU databases for the period between 1994 and 2023, in accordance with PRISMA 2020 guidelines. The review included publications that addressed the biological properties of solutions for preserving the viability of teeth in traumatic dental injuries.

RESULTS: The search yielded 252 articles. Following screening and full-text analysis, 36 articles comparing the efficacy of different transportation media were included in the review. The literature review identified 34 different solutions, with the efficacy assessed by viable periodontal cell counts. The analyzed solutions included Hank’s balanced salt solution, various types of milk, propolis, coconut water, and many others. The studies revealed considerable differences in the efficacy of analyzed solutions, storage conditions, and viable cell evaluation methods. The MTT assay and trypan blue were the most frequently used laboratory tests for assessing metabolic activity. According to the majority of authors, Hank’s balanced salt solution and milk were the best storage media for preserving the viability of tooth tissues.

CONCLUSION: The studies assessing solutions for preserving the viability of tooth cells in traumatic dental injuries highlight the need for more accessible and effective transportation media due to inconsistent data on their biological efficiency; further research is required.