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Objective. The aim was to evaluate the flexural strength, flexural modulus, microhardness, Weibull modulus, and characteristic strength of six resin composite blocks (Grandio Blocs-GR, Tetric CAD-TE, Brilliant Crios-CR, Katana Avencia-AV, Cerasmart-CS, and Shofu Block HC-HC). Methods. Flexural strength and flexural modulus were measured using a three-point bending test and microhardness using the Vickers method. Weibull analysis was also performed. Results. The materials showed flexural strength ranging from 120.38 (HC) to 186.02 MPa (GR), flexural modulus from 8.26 (HC) to 16.95 GPa (GR), and microhardness from 70.85 (AV) to 140.43 (GR). Weibull modulus and characteristic strength ranged from 16.35 (CS) to 34.98 (TE) and from 123.45 MPa (HC) to 190.3 MPa (GR), respectively. Conclusions. GR, TE, and CR presented significantly higher flexural strength, modulus, Weibull modulus, and characteristic strength than the others.

Introduction. Functional treatment is the type of treatment preferred in young patients with lateral bite because it leads to simultaneous improvement of occlusion and facial profile. Objective. The aim of this study is to assess bone changes within the condylar process of the mandible and to associate them with the changes observed in the analysis of lateral cephalograms and in the patient’s occlusion. Materials and Methods. Cone beam tomography of the temporomandibular joint, lateral radiogram of the skull, was performed at the beginning of treatment and after one year of therapy. Changes in cephalometric radiograms were evaluated by analyzing them and shown by making superimposition and staining layers. For the purpose of assessing bone changes within the condylar process, digital 3D solids of these processes were generated using data from computed tomography. Results. Correction towards Angle’s dental class I, overjet reduction from 8 mm to 3 mm, and improvement of the patient’s profile were obtained. A rotation of the occlusal plane and improvement in an ANB by 1° and in the WITS measurement by 2.7 mm were observed. A growth of the condylar processes “backwards” and “upwards” was also observed, as well as a change of their shape and volume. Conclusions. The obtained results suggest that the patient’s significant improvement in occlusal conditions is due to posterior growth stimulation of the condylar processes of the mandible. The results confirm the validity of using this treatment technique in the case of growing children with complete posterior occlusion.

Purpose. The aim of this work was to compare the temperature fluctuations that occur during the development of the implant bed using three different implant systems and the impact on their value of cooling method and rotational speed of drill. Material and Methods. As a model of the human jaw due to the analogy of bone structure and hardness, pig ribs were used. Drills from three different implant systems were used in the study: Straumann® (Straumann GmbH, Basel, Switzerland), AnyRidge® (Megagen Implant Co., Ltd., Daegu, South Korea), and Osstem (OSSTEM IMPLANT CO., LTD., Seoul, South Korea). The sequence of three successive drills was given—from pilot drill to final drill. For each system, a group with two water cooling methods, without cooling, and three different speed ranges, 800, 1200, and 1500 rpm, and their effect on temperature fluctuations was evaluated. The temperature was measured by thermography. Results. The highest temperature increases were noted during preparation with pilot drills. The maximum temperature (50.8°C) was noted for the AnyRidge pilot drill at 1500 rpm without cooling. When cooling with physiological saline, none of the applied drills exceeded 28°C. Significant differences between lack of cooling and cooling with saline at 20°C and 3°C have been demonstrated. During preparation with cooling, the difference between the times of the maximum temperature achievement was observed between AnyRidge® and Osstem (2.6 vs. 1.6 s, p=0.004). Conclusion. The experiment showed that the drills of the tested implant systems differed in the amount of heat generated during operation. The temperature of the cooling solution and the rotational speed applied have an influence on its amount.

Objective. Clinical comparison of the survival rates between stainless steel and ceramic brackets over a 12-month period. Materials and Methods. The study involved 20 consecutive patients with diagnosed malocclusion that required two-arch fixed appliance treatment. The participants were randomly divided into two 10-member groups. Group 1 was treated with Abzil Agile (3M Unitek) stainless steel brackets; group 2 was treated with Radiance (American Orthodontics) monocrystalline ceramic brackets. All the brackets were bonded by the same operator. Over the next 12 months, all bracket failures were recorded with each appointment. The received data were processed statistically using the Mantel–Cox test, Kaplan–Meier method, and Cox hazard model. Results. A total of 381 brackets were bonded, 195 of which were metallic brackets and 186 were ceramic ones. In the 12-month observation period, there were 14 metal (7.2%) and 2 ceramic bracket (1.1%) failures. The overall failure rate was 4.2% (n = 16). The majority of failures (14 brackets; 87.5%) occurred during the first 6 months of the experiment, 12 (83%) of which were metal brackets and 2 (100%) were ceramic brackets. The statistical analysis revealed significant differences between the groups (p<0.05). Conclusions. Metal brackets demonstrated significantly higher failure rates than ceramic brackets for both 6- and 12-month observation periods (p<0.05). The 6% difference between the brackets is clinically significant as it corresponds to one additional failure within 12 months.

The aim of this article was to present a characteristic clinical image of Melnick–Needles syndrome using an example of an 11.5-year-old female patient treated at the Facial Congenital Disorders Outpatient Clinic as well as to present the actual literature review of the surgical treatment. The patient was diagnosed with several characteristics typical for Melnick–Needles syndrome: single-sided hearing loss, malocclusion, and facial dysmorphism, among others. Due to malocclusion and facial dysmorphism, the patient with Melnick–Needles syndrome requires orthodontic treatment with surgical intervention. Mandibular distraction with fixed appliance treatment is a recommended treatment protocol.

Aim. The aim of this study was to assess the electrical activity of temporalis and masseter muscles in children with cleft lip and palate (CLP) and pain-related temporomandibular disorders (TMD-P). Methods. The sample consisted of 31 CLP patients with a TMD-P (mean age 9.5 ± 1.8 years) and 32 CLP subjects with no TMD (mean age 9.2 ± 1.7 years). The children were assessed for the presence of temporomandibular disorders (TMD) using Axis I of the Research Diagnostic Criteria for TMD (RDC/TMD). Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany) in the mandibular rest position and during maximum voluntary contraction (MVC). Results. The rest activity of the temporalis and masseter muscles was significantly higher in TMD-P group compared with non-TMD children. A significant decrease in temporalis muscle activity during MVC was observed in TMD-P patients. There was a significant increase in the Asymmetry Index for temporalis and masseter muscle rest activity in the TMD-P group. Conclusion. Cleft children diagnosed with TMD-P have altered masticatory muscle activity, and this can affect their muscle function.