Search Results (9)

Aim: Class II Division I malocclusion poses significant challenges in orthodontics. The combination of a Herbst appliance and miniscrew anchorage emerged as a practical solution to improve skeletal and dental outcomes. This study employed finite element analysis to evaluate the biomechanical effects of a miniscrew-supported Herbst appliance on mandibular advancement and dentition movement. Methods: High-definition CBCT scans captured the maxilla and mandible’s detailed dental anatomy. The scans were stored in DICOM format for seamless integration with Mimics software (Mimics Innovation Suite research version 21.0, Materialise NV, Leuven, Belgium) for 3D reconstruction and model refinement. The appliance, designed with a maxillary fixed palatal arch and mandibular acrylic splint connected by telescoping rods, incorporated titanium TADs and elastic chains. STL models were optimized in Geomagic x Design for finite element analysis in Abaqus, assigning validated mechanical properties for materials. Tetrahedral meshing and realistic boundary conditions simulated biomechanical interactions. Tetrahedral C3D4 elements were used for meshing, ensuring a balance between computational efficiency and detailed anatomical representation. Tetrahedral meshing and realistic boundary conditions simulated biomechanical interactions. Dynamic simulations in CATIA evaluated mandibular movement. FEA analyzed displacement across dentoalveolar structures along the X, Y, and Z axes to assess treatment efficacy and biomechanical stability. Results: The Z displacement analysis revealed that the incisal edges of the lower central, lateral, and canines shifted lingually by 0.41, 0.4, and 0.47 mm, respectively. Additionally, the apices of the lower central, lateral, and canines displaced backwards by 0.05 mm, 0.05 mm, and 0.07 mm, respectively. Conclusions: The appliance facilitated mandibular advancement, bodily retracted the lower incisors, well-controlled the upper ones, and mesial-tipped the upper posterior teeth. In contrast with traditional functional appliances, it caused the lower anterior teeth to move backwards, while skeletal anchorage overcame some shortcomings of nonsurgical treatments. This method might be a good treatment option for growing skeletal Class II patients. Full article

Objectives: The treatment of class II patients with mandibular retrusion often involves the use of a Herbst appliance, due to its efficiency and reduced need for compliance. Despite skeletal benefits, undesired dental effects, caused by anchorage loss, could reduce mandibular advancement, especially after the pubertal peak. Although the period between cervical vertebral maturation (CVM) 3 and CMV4 is considered the best choice to maximize the orthopedic outcome, clinicians cannot always treat patients during this ideal time window, as they present at their first visit later. The goal of this study is to evaluate whether the combination of an acrylic splint Herbst appliance with skeletal anchorage and elastic chains in both the upper and lower arch (Skeletal Therapy Manni Telescopic Herbst 4: STM4) could improve the efficiency of functional treatment also in CVM 5–6 patients. Methods: Lateral cephalograms of 10 consecutively treated patients taken at the beginning and at the end of the Herbst phase were analyzed and compared with those of 10 untreated patients of the same sex, age, malocclusion, and skeletal maturation. Results: According to the Pancherz analysis, the treated group of patients showed the significant advancement of the pogonion (4.75 mm), with a reduction in ANB (−3.3°) and Wits (−4.15 mm). The combination of miniscrews and elastic ligatures allowed the labial tipping of the upper incisors (+6.65°) and limited the labial flaring of the lower ones (+3.05°), maintaining the overjet needed for mandibular advancement. Conclusions: The STM4 technique might be an effective protocol for skeletal class II correction after the pubertal peak since it significantly reduces unfavorable dental compensations, increasing the skeletal effects and the esthetic outcome of the orthopedic treatment. Full article

The effects of occlusal splints on sport performance have already been studied, although their biomechanical impacts are often overlooked. We investigated the kinematical changes during running until exhaustion at severe intensity while wearing a mandibular advancement occlusal splint. Twelve trained runners completed (i) an incremental protocol on a track to determine their velocity corresponding to maximal oxygen uptake and (ii) two trials of square wave transition exercises at their velocity corresponding to maximal oxygen until exhaustion, wearing two occlusal splints (without and with mandibular advancement). Running kinematics were compared within laps performed during the square wave transition exercises and between splint conditions. The mandibular advancement occlusal splint increased the running distance covered (~1663 ± 402 vs. 1540 ± 397 m, p = 0.03), along with a noticeable lap effect in decreasing stride frequency (p = 0.04) and increasing stride length (p = 0.03) and duty factor (p < 0.001). No spatiotemporal differences were observed between splints, except for improved balance foot contact times in the mandibular advancement condition. An increased knee flexion angle at initial contact (p = 0.017) was noted along laps in the non-advancement condition, despite the fact that no differences between splints were found. Running patterns mainly shifted within laps rather than between conditions, indicating that a mandibular advancement occlusal splint had a trivial kinematical effect. Full article

Background/Objectives: Surgical navigation has advanced maxillofacial surgery since the 1990s, bringing benefits for various indications. Traditional registration methods use fiducial markers that are either invasively bone-anchored or attached to a dental vacuum splint and offer high accuracy but necessitate additional imaging with increased radiation exposure. We propose a novel, non-invasive registration protocol using a CAD/CAM dental splint based on high-resolution intraoral scans. Methods: The effectiveness of this method was experimentally evaluated with an ex vivo 3D-printed skull measuring the target registration error (TRE). Surgical application is demonstrated in two clinical cases. Results: In the ex vivo model, the new CAD/CAM-splint-based method achieved a mean TRE across the whole facial skull of 0.97 ± 0.29 mm, which was comparable to traditional techniques like using bone-anchored screws (1.02 ± 0.23 mm) and dental vacuum splints (1.01 ± 0.33 mm), while dental anatomical landmarks showed a lower accuracy with a mean TRE of 1.84 ± 0.44 mm. Multifactorial ANOVA confirmed significant differences in TRE based on the registration method and the navigated level of the facial skull (p < 0.001). In clinical applications, the presented method demonstrated high accuracy for both midfacial and mandibular surgeries. Conclusions: Our results suggest that this non-invasive CAD/CAM-splint-based method is a viable alternative to traditional fiducial marker techniques, with the potential for broad application in maxillofacial surgery. This approach retains high accuracy while eliminating the need for supplementary imaging and reduces patient radiation exposure. Further clinical trials are necessary to confirm these findings and optimize splint design for enhanced navigational accuracy. Full article

Background: Tooth infraocclusion is a process in which a completely or partially erupted tooth gradually moves away from the occlusal plane. Submerged teeth can lead to serious complications. Treating teeth with infraocclusion is very challenging. One of the procedures allowing for the replacement of a missing tooth is autotransplantation. The aim of this paper is to review the literature on teeth autotransplantation, supported by a case report involving the autotransplantation of a third mandibular molar into the site of an extracted infraoccluded first mandibular molar, as well as the utilization of advanced platelet-rich fibrin (A-PRF) alongside autogenous dentin grafts for bone tissue regeneration. Methods: A severely infraoccluded first permanent right mandibular molar was extracted and then ground to obtain the dentin graft. A-PRF clots (collected from the patient’s peripheral blood) were added to the autogenous dentin graft, to create the A-PRF membrane. An atraumatic extraction of the lower left third molar was performed and then it was transplanted into the socket of tooth no. 46. Immediately after transplantation, tooth no. 38 was stabilized with orthodontic bracket splints for 3 months. The patient attended regular follow-up visits within 12 months. Results: After one year, the patient did not report any pain. In the clinical examination, the tooth and surrounding tissues did not show any signs of infection. However, radiographically, cervical inflammatory resorption, unchanged pulp canal dimensions, absent root growth, periapical radiolucency, and lack of apical and marginal healing were observed. Reconstruction of the bone defect was obtained and the alveolar ridge of the mandible was preserved. Due to poor stability of the tooth and severe resorption, the tooth needed to be extracted. Conclusions: This study is designed to critically evaluate the efficacy of autotransplantation, the application of growth factors, and the integration of autogenous dentin grafts in remedying dental deficiencies resulting from reinclusion. We aim to point out the possible causes of treatment failure. Full article

Background: Mandibular Advancement Devices (MADs), inserted in non-surgical treatments for obstructive sleep apnea and hypopnea syndrome (OSAHS), are used intra-orally during the sleep period, with the aim of promoting mandibular protrusion. The aim of the study is to analyze the changes in the upper airway after the use of an MAD in the treatment of OSAHS. Methods: 60 patients diagnosed with OSAHS, as established by the Sleep Medicine Service, underwent treatment with the Silensor SL device at the Stomatology Service of the University Hospital Center of Coimbra, from January 2018 to January 2019. All patients completed two polysomnographies and two lateral teleradiographies: one before starting treatment (T0) and one after 1 year of treatment (T1). In the lateral teleradiography performed after one year of treatment, the patient had the MAD placed intra-orally. The linear measurements of the airspace proposed by the Arnett/Gunson FAB Surgery cephalometric analysis were measured at four craniometric points: A, MCI, B, Pog. Results: The results demonstrate an anteroposterior airway enlargement in two of the four points studied with the MAD placed intra-orally (B and Pog point). The greatest average increase is observed at point Pog (3 mm), followed by B (1 mm), and finally, point A (0.6 mm). Conclusions: This study proved that there is an improvement in anteroposterior measurements at various points in the upper airways after treatment with MAD. Full article

The genioglossus is a major upper airway dilator muscle. Our goal was to assess the efficacy of upper airway muscle training on Obstructive Sleep Apnea (OSA) as an adjunct treatment. Sixty-eight participants with OSA (AHI > 10/h) were recruited from our clinic. They fall into the following categories: (a) Treated with Automatic Positive Airway Pressure (APAP), (n = 21), (b) Previously failed APAP therapy (Untreated), (n = 25), (c) Treated with Mandibular Advancement Splint (MAS), (n = 22). All subjects were given a custom-made tongue strengthening device. We conducted a prospective, randomized, controlled study examining the effect of upper airway muscle training. In each subgroup, subjects were randomized to muscle training (volitional protrusion against resistance) or sham group (negligible resistance), with a 1:1 ratio over 3 months of treatment. In the baseline and the final visit, subjects completed home sleep apnea testing, Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), SF-36 (36-Item Short Form Survey), and Psychomotor Vigilance Test (PVT). Intervention (muscle training) did not affect the AHI (Apnea-Hypopnea Index), (p-values > 0.05). Based on PSQI, ESS, SF-36 scores, and PVT parameters, the changes between the intervention and sham groups were not significant, and the changes were not associated with the type of treatment (p-value > 0.05). The effectiveness of upper airway muscle training exercise as an adjunct treatment requires further study. Full article

Obstructive sleep apnea (OSA), which is caused by obstructions of the upper airway, is a syndrome with rising prevalence. Mandibular advancement splints (MAS) are oral appliances for potential treatment of OSA. This work proposes a highly-sensitive pressure sensing array integrated with a system-on-chip (SoC) embedded in a MAS. The device aims to measure tongue pressure distribution in order to determine the efficacy of the MAS for treating OSA. The flexible sensing array consists of an interdigital electrode pair array assembled with conductive polymer films and an SoC capable of retrieving/storing data during sleep, and transmitting data for analysis after sleep monitoring. The surfaces of the conductive polymer films were patterned with microdomed structures, which effectively increased the sensitivity and reduced the pressure sensing response time. The measured results also show that the crosstalk effect between the sensing elements of the array was negligible. The sensitivity of the sensing array changed minimally after the device was submerged in water for up to 100 h. Full article

The treatment of infected mandibular fractures has advanced rather dramatically over the past 50 years. Immobilization with maxillomandibular fixation and/or splints, removal of diseased teeth in the fracture line, external fixation, use of antibiotics, debridement, and rigid internal fixation has played a role in management. Perhaps the most important advance was the realization that infected fractures also result from moving fragments and nonvital bone, not just bacteria. Controlling movement and eliminating the dead bone allowed body defenses to also eliminate bacteria. The next logical step in the evolution of treatment was primary bone grafting of the resulting defect following application of rigid internal fixation and debridement of the dead bone. We offer our results with this treatment in 21 infected fractures, 20 of which achieved primary union. Full article