Igor. A. Voronov

Aim. To systematically evaluate the efficacy of diode lasers (810, 940, and 980 nm) as an adjunct to scaling and root planing (SRP) in the treatment of chronic periodontitis. Material and methods. A systematic search was conducted in PubMed/MEDLINE, PMC, Cochrane Library, CyberLeninka, and eLibrary.ru databases for the period 2008—2024 following PRISMA guidelines. Only randomized controlled trials (RCTs) comparing SRP combined with diode laser therapy vs. SRP alone in adult patients with chronic periodontitis were included. Results. Ten RCTs (n=287 patients total) met the inclusion criteria. Adjunctive diode laser therapy resulted in statistically significant additional reduction in probing pocket depth (PPD) of 0.32 mm (95% CI: 0.15—0.45) and clinical attachment level (CAL) gain of 0.18—0.35 mm (95% CI: 0.12—0.52) compared to SRP alone. The most pronounced effect was observed with 810 nm and 980 nm lasers. No serious adverse events were reported. Conclusion. Adjunctive diode laser application is safe and provides statistically significant improvements in periodontal clinical parameters. The clinical magnitude of the benefit is modest and most pronounced in moderate-depth pockets (4—6 mm).

Relevance. Temporary plastic bridge prostheses supported by dental implants, used in immediate loading protocols, often fail due to fracture of the internal reinforcing framework. The optimal configuration of a 1 mm diameter titanium wire framework remains unclear. Objective — to perform a comparative analysis of four titanium wire framework configurations under vertical and combined loads (up to 800 N) with safety factor calculation and selection of the optimal topology. Materials and methods. Four models of a temporary bridge prosthesis (12 artificial teeth, 4 implants) were analyzed using the finite element method in ANSYS 22.5. Configuration №1 — single lingual wire; №2 — single buccal wire; №3 — two alternating (lingual/buccal) bent wires; №4 — two alternating straight welded fragments. Pre-tension of screw joints (548 N and 278 N) was simulated. Loading scenarios: vertical 250 N and 500 N on incisors; combined 500 N and 800 N on occlusal surfaces. Results. Under combined 500 N load, configuration №2 showed critical stresses (956.28 MPa, safety factor 0.87). Under 800 N load, all configurations had safety factor <1.0 (0.87—0.97). Configuration №4 (alternating welded fragments) demonstrated the lowest peak stress (856.20 MPa), lowest mean stress (125.53 MPa), lowest standard deviation (125.64 MPa), and lowest interquartile range (126.88 MPa). Increasing the wire diameter to 1.25 mm yields a predicted safety factor of 1.51. Conclusion. The spatial alternating welded framework (configuration №4) provides superior stress distribution. A 1 mm diameter is insufficient for 800 N loads. Increasing the diameter to 1.25—1.3 mm is recommended. The single buccal wire configuration is contraindicated.

AIM. Evaluation of the parameters of microhardness and elastoplastic deformation of the dentine of the roots of untreated teeth for further use in experimental studies devoted to the search for protocols that minimally weaken the root structures during endodontic treatment. MATERIALS AND METHODS. 14 premolars (9 upper and 5 lower) with a straight root, removed according to orthodontic indications, were selected for the study. The root of each tooth was divided into three parts (oral, middle, and apical), then the parameters of microhardness and elastic plastic deformation were determined for each of the parts. Measurements were carried out in three areas: at the channel, in the middle part of the sample and in the outer part of the sample. RESULTS. Microhardness parameters: the middle segment has the highest microhardness values for all thirds of the root: in the mouth – 95.02 (91.97–99.31) HV, 1026.05 (993.03–1072.37) (MPa), average – 97.34 ± 12.45 HV, 1051.11 ± 134.47 (MPa) and apical-100.08 ± 12.35 HV, 1080.69 ± 133.33 (MPa). Parameters of elastoplastic deformation: the middle segment has the highest modulus of elasticity in all thirds of the root, the highest index is in the apical third of the root – 24.25 (24.01–25.30) (MPa), the lowest is in the middle third (21.87 ± 1.55 MPa); the highest relative work of elastic deformation is in the middle third of the root, the lowest is in the mouth a third. At the same time, it increases from the mouth to the middle third, and decreases from the middle third to the apical third. The greatest relative work of plastic deformation is in the estuarine third, the smallest is in the middle third, while it decreases from the estuarine to the middle third, and increases from the middle third to the apical third. CONCLUSIONS. The apical third of the root is the hardest, while the middle third is the most elastic. When considering the wall in a cross-section, the middle is the hardest, while the segments at the channel and at the outer edge are less hard and more elastic.

BACKGROUND: The relevance of this study is supported by the integration of modern technologies into dental practice, including the use of surgical guides. Unfortunately, in recent years, foreign materials have often been either unavailable for purchase or prohibitively expensive. The use of materials produced in Russia ensures consistent availability, faster delivery, and competitive pricing. This study evaluates the physicomechanical properties of Russian-made materials used for fabricating surgical guides and determines how these properties change after sterilization by autoclaving. AIM: This work aimed to assess the physicomechanical properties of Russian 3D printing materials intended for surgical guide fabrication before and after autoclave sterilization. METHODS: Three types of domestically produced photopolymer resins were tested. Hardness, flexural modulus, and fracture toughness were evaluated before and after sterilization. RESULTS: Flexural testing demonstrated that all three groups of Russian materials are suitable for use as finished surgical guides in accordance with the requirements of GOST R 71413-2024 Dentistry. Base Polymers. Part 2: Polymeric Orthodontic Base Materials. General Technical Requirements and Test Methods, which specifies a minimum flexural strength of 50 MPa and a minimum elastic modulus of 1500 MPa for the fabrication of bases intended for prolonged intraoral use. All tested material groups met these requirements, except the group 1 (“wet”) samples. However, because a surgical guide does not stay in the oral cavity for long and does not have sufficient time to absorb moisture, and because the mechanical load on a navigation guide is substantially lower, group 1 materials may also be recommended for guide fabrication. Autoclaved samples from groups 1 and 2 demonstrated high fracture toughness values. In turn, group 3 samples remained stable, which may indicate a homogeneous internal structure of the material. CONCLUSION: Material strength increased after autoclave sterilization. All tested material groups are suitable for fabrication of surgical guides, with group 3 demonstrating the most stable physicomechanical properties.

Objective: to study the dietary habits among student youth and identify the risk group for the development of a cariogenic oral cavity based on nutritional parameters.Materials and methods: the survey included 199 students (89 male, 100 female). Among them, 49 were second-year students, 41 were third-year students, 52 were fourth-year students, and 57 were fifth-year students. All participants were students at Vietnam National University in Hanoi. The mean age of respondents was 22 years. An anonymous questionnaire was administered in paper format in respondent’s native language (Vietnamese). The questionnaire consisted of 24 questions, students could select multiple options from predefined answers or write in their preferences. Responses were statistically analyzed using StatTech software version 4.5.0 (Russian Federation).Results: breakfast was the most frequently skipped meal (25 students (12,6 %)). Most students adhered to three main daily meal, 140 (70,4%) reported frequent snacking. Bubble-tea was preferred by 77 participants (38,7%), with sweet foods being the dominant preference overall. During examination periods, 67 students (33,7%) altered their dietary habits, of whom 65 (97% of this subgroup) consumed instant noodles (Doshirak).Conclusion: implementation of nutritional education initiatives and restriction of sugar-sweetened beverage sales in university canteens, recommended replace them with water and unsweetened juices.

   Aim. Destructive changes in the tissues of the tooth and periodontium entail resorption of the hard tissues of the tooth in the apical region. The goal is to identify morphological changes in root tissues with destructive periodontitis and resorption phenomena after the treatment of the tooth with calcium-containing preparations using a scanning electron microscope.   Materials and methods. Examination of teeth treated for destructive forms of periodontitis with apical resorption was performed using a JSM-6490LV scanning electron microscope (JEOL, Japan) with an energy-dispersive attachment INCA Penta FETx3 (OXFORD Instruments, England).   Results. In the apical part of the root there is a cellular mixed layered cementum. The dentin and the dentin-cementum junction are highly calcified. On top of them is cellular cement with lacunae of cementoblasts. The relief of the zone of cell-free cement has a wavy structure, consists of dense collagen fibers with a high content of calcium. With external root resorption, we observe extensive destruction of the cementoblast layer. An area of newly formed cementum was found inside the apical foramen. On the apical surface, where the resorption covered the dentin layer, there was an area of newly formed cementum. Its cellular layer consisted of round-shaped cells rising above the tissue of a homogeneous structure, smoothly flowing into the spongy tissue denting the bone.   Discussion. It can be assumed that prolonged use of calcium-containing drugs leads to calcification. The presence of dense connective tissue in the periodontium indicates regenerative processes. The control of cement formation remains uncertain.   Conclusions. Perhaps we are seeing a reparative atypical regeneration of the cement of the apical part of the tooth root. Dentinal calcification. In the lateral parts of the apical region, there is an outer layer of cementum with no cementoblasts. An increase in the thickness of the cement was noted. It can be assumed that we observe the phenomenon of osteogenesis in the area of strong resorption.

BACKGROUND: Immediate implant placement and immediate loading after maxillary central incisor extraction are of great importance. Implant placement with immediate loading is the most preferred method of treatment in the long term. The anatomical constrictions of the maxilla make implant placement difficult. To achieve primary stability and make a screw-retained crown, dental surgeons are forced to fix the implant placing it toward the palatal wall. When the implant is placed this way, the crown will be bulkier than the one of the extracted tooth. This change in anatomy can lead to patient discomfort and some parafunctions (in speech, chewing, etc.). AIM: To assess the potential discomfort in patients with changes in the crown anatomy of maxillary central incisors after implant-supported prosthetics. METHODS: Fifty students (25 men and 25 women) underwent intraoral scanning with the 3Shape scanner. A possible increase in the crown volume was simulated in ExoCAD at a rate of an implant + titanium base + layer of structural material with zirconium dioxide as an example, on average equal to 34 mm. Onlays imitating the increased crown volume were milled and fixed in the oral cavity of the participants on tooth 1.1, and further examinations were conducted. RESULTS: The examination revealed that the crown anatomy change brought some discomforts in most of the respondents whose speech and eating were affected. CONCLUSION: The results reveal that a change in the anatomical shape of the crown during implant-supported prosthetics can affect vital functions and cause discomfort. More attention is needed to implant placement planning, taking into account further prosthetics in the esthetic area. Therefore, the use of angulated implants is encouraged.

Background: Success of immediate implant placement in the area of maxillary central incisor greatly depends on the degree of tightening of the fixing screw of the fully zirconia crowns. For treatment of this kind, clinicians use implants of various designs and implants with angled abutments to bypass anatomical limitations, achieve primary implant stability, and fabricate a screw-retained crown. However, the crown fabricated for the implant placed can experience non-axial loads during occlusion, which can lead to screw loosening and adversely affect treatment success, especially in the early post-operative period. Objective: to perform a comparative analysis of the effect of cyclic loading on the reliability of the fixing screw in full zirconia crowns supported by angled implants with platform inclination of 12, 24, 36, by straight implants and straight implants with angled abutments. Materials and methods: the degree of the prosthetic screw tightening was studied in 30 samples, 6 groups of 5 implants (straight implants, straight implants with standard 17 angled abutments and 12 custom abutments, angled implants with platform inclination of 12, 24, and 36. A full zirconia crown of maxillary central incisor was fabricated and fixed on every implant and subsequently exposed to cyclic loading up to 1*106 cycles. Afterwards, the maximum unscrewing torque was determined for each group. Statistical analysis was carried out. Results: the minimum values of the maximum torque were 20.8040.01 N/cm for the group of straight implants with 17 angled abutments, and the maximum values for the group of straight implants were 22.820.04 N/cm. There was no significant difference in values between the straight and angled implant groups. However, the values in these groups were higher compared to the groups of implants with angled abutments. Conclusion: the study showed that fixing screws are more reliable in crowns supported by straight implants and angled implants with different platform inclinations. Therefore, these implants are the most preferred option for immediate implant placement in the anterior region.

BACKGROUND: Immediate implant placement to the fresh socket of the extracted tooth, with immediate loading, is well documented. Dental roots in proximity to the vestibular plate require thorough attention from clinicians. Implants placed close to the vestibular plate often lead to its resorption and gingival recession. Therefore, dental surgeons place implants 23 mm away from the vestibular plate. In turn, prosthodontists plan implant placement so that the screw channel is not on the vestibular surface, which is most significant in the aesthetic area. However, this is not always possible, and there is a conflict between implant placement with proper primary stability and its simultaneous loading with a screw-retained crown. AIM: To conduct radiological assessment of the ideal implant placement for a screw-retained crown. MATERIALS AND METHODS: A total of 120 cone-beam computed tomography (CBCT; 3 groups of 40 people with different root positions) were analyzed. In each group, the possibility of extracting tooth 1.1 and inserting an implant was evaluated in compliance with the protocol for immediate implantation and the possibility to have the screw shaft of the artificial crown on the palatal surface. RESULTS: Group C was defined as the most favorable for immediate implant placement with a screw-retained crown. The least favorable was group N. In total, the screw channel in 40% of the cases was located palatally, 26.6% to the incisal edge, and 33.3% on the vestibular surface. CONCLUSIONS: Careful analysis of CBCT when planning implant-supported restoration in the aesthetic area is an integral part of the treatment. A team approach is required from surgeons and prosthodontists when planning. In a larger percentage of cases, implant-supported prosthetics in the maxillary central incisors involve the use of alternative solutions for the restoration of screw-retained crowns.

Lack of adequate width and thickness of periodontal or peri-implant soft tissues can compromise the aesthetics, function or survival of teeth and dental implants. Biomaterials are widely used in dentistry to overcome the disadvantages of autogenous tissue transplantation. The advantage of using biomaterials is that there is no need for re-surgery and that they are available in large quantities. The most widely used biomaterial for soft tissue augmentation is collagen, as it is believed to best mimic the natural cellular environment of the extracellular matrix, although other biomaterials are also candidates for soft tissue regeneration. Collagen matrices differ in composition, three-dimensional structure, elasticity and mechanical stability. Aim. is to review the literature on the optimization of regeneration at the stages of soft tissue augmentation using a collagen matrix.