New clinical application of digital intraoral scanning technology in occlusal reconstruction:A case report

BACKGROUND Digital intraoral scanning,although developing rapidly,is rarely used in occlusal reconstruction.To compensate for the technical drawbacks of current occlusal reconstruction techniques,such as time consumption and high technical requirements,digital intraoral scanning can be used in clinics.This report aims to provide a way of selecting the most suitable maxillo-mandibular relationship(MMR)during recovery.CASE SUMMARY A 68-year-old man with severely worn posterior teeth underwent occlusal reconstruction with fixed prosthesis using digital intraoral scanning.A series of digital models in different stages of treatment were obtained,subsequently compared,and selected using digital intraoral scanning together with traditional measurements,such as cone beam computed tomography,joint imaging,and clinical examination.Using digital intraoral scanning,the MMR in different stages of treatment was accurately recorded,which provided feasibility for deciding the best occlusal reconstruction treatment,made the treatment process easier,and improved patient satisfaction.CONCLUSION This case report highlights the clarity,recordability,repeatability,and selectivity of digital intraoral scanning to replicate and transfer the MMR during occlusal reconstruction,expanding new perspectives for its design,fabrication,and postoperative evaluation.

A retrospective study of occlusal reconstruction in patients with old jaw fractures and dentition defects

Purpose:This study evaluated the methods and clinical effects of multidisciplinary collaborative treatment for occlusal reconstruction in patients with old jaw fractures and dentition defects.Methods:Patients with old jaw fractures and dentition defects who underwent occlusal reconstruction at the Third Affiliated Hospital of Air Force Military Medical University from January 2018 to December 2022 were enrolled.Clinical treatment was classified into 3 phases.In phase I,techniques such as orthognathic surgery,microsurgery,and distraction osteogenesis were employed to reconstruct the correct 3-dimensional(3D)jaw position relationship.In phase II,bone augmentation and soft tissue management techniques were utilized to address insufficient alveolar bone mass and poor gingival soft tissue conditions.In phase III,implant-supported overdentures or fixed dentures were used for occlusal reconstruction.A summary of treatment methods,clinical efficacy evaluation,comparative analysis of imageological examinations,and satisfaction questionnaire survey were utilized to evaluate the therapeutic efficacy in patients with traumatic old jaw fractures and dentition defects.All data are summarized using the arithmetic mean±standard deviation and compared using independent samplet-tests.Results:In 15 patients with old jaw fractures and dentition defects(an average age of 32 years,ranging from 18 to 53 years),there were 7 cases of malocclusion of single maxillary fracture,6 of malocclusion of single mandible fracture,and 2 of malocclusion of both maxillary and mandible fractures.There were 5 patients with single maxillary dentition defects,2 with single mandibular dentition defects,and 8 with both maxillary and mandibular dentition defects.To reconstruct the correct 3D jaw positional relationship,5 patients underwent Le Fort I osteotomy of the maxilla,3 underwent bilateral sagittal split ramus osteotomy of the mandible,4 underwent open reduction and internal fixation for old jaw fractures,3 underwent temporomandibular joint surgery,and 4 underwent distraction osteogenesis.All patients underwent jawbone augmentation,of whom 4 patients underwent a free composite vascularized bone flap(26.66%)and the remaining patients underwent local alveolar bone augmentation.Free gingival graft and connective tissue graft were the main methods for soft tissue augmentation(73.33%).The 15 patients received 81 implants,of whom 11 patients received implant-supported fixed dentures and 4 received implant-supported removable dentures.The survival rate of all implants was 93.82%.The final imageological examination of 15 patients confirmed that the malocclusion was corrected,and the clinical treatment ultimately achieved occlusal function reconstruction.The patient satisfaction questionnaire survey showed that they were satisfied with the efficacy,phonetics,aesthetics,and comfort after treatment.Conclusion:Occlusal reconstruction of old jaw fractures and dentition defects requires a phased sequential comprehensive treatment,consisting of 3D spatial jaw correction,alveolar bone augmentation and soft tissue augmentation,and implant-supported occlusal reconstruction,achieving satisfactory clinical therapeutic efficacy.

Application Progress of Digital Occlusion Analysis in Occlusal Reconstruction

Occlusal disorder caused by severe worn dentition is one of the most common diseases in the occlusion. Occlusal reconstruction is an important repair method, referring to modify and rebuild the existing occlusion status, then to restore the occlusion. During occlusal reconstruction, the digital occlusion analysis system can accurately acquire the occlusion status, in order to guide the reconstruction occlusion accurately and restore the normal function of the oral maxillary system. This paper reviews the concept of occlusal reconstruction, sequence therapy, traditional occlusion analysis methods and the development status and prospect of digital occlusion analysis.

Intermittent blood flow restriction does not reduce atrophy following anterior cruciate ligament reconstruction

Background:A previous study has reported a 50% reduction in disuse atrophy of the quadriceps during the first 14 days after anterior cruciate ligament(ACL) reconstruction.A follow-up trial is needed to confirm these promising results.The present study aims to investigate the effect of an occlusion stimulus on quadriceps atrophy after ACL reconstruction.Methods:A total of 24 subjects participated in the study.They were randomized into two groups.Starting the 2nd day after surgery,the occlusion group received an occlusion stimulus for 5 min,followed by removal of the occlusive pressure for 3 min.This was repeated five times in one training session,twice daily.During the period of occlusive stimulus,the subjects performed 20 low load exercises for the quadriceps.The control group followed the same exercise protocol,but without the occlusion stimulus.Changes in quadriceps anatomical cross section area(ACSA) were measured using axial magnetic resonance(MR) images at 40% and 50% of the length of the femur.Results:Both groups had a significant reduction of quadriceps ACSA from 2 days before surgery to 16 days after surgery.During the intervention period,the occlusion group lost 13.8% ± 1.1%(mean ± SEM) and the control group lost 13.1% ± 1.0% of their quadriceps ACSA,respectively.There was no significant difference between the occlusion and control groups with regards to atrophy of the quadriceps muscles.Conclusion:In conflict with other studies using a similar protocol,application of blood flow restriction the first 14 days after ACL reconstruction did not reduce quadriceps ACSA muscle atrophy measured by MR in a population of athletes.

Regeneration of elemental images in integral imaging for occluded objects using a plenoptic camera

In this Letter, we propose an elemental image regeneration method of three-dimensional（3D） integral imaging for occluded objects using a plenoptic camera. In conventional occlusion removal techniques, the information of the occlusion layers may be lost. Thus, elemental images have cracked parts, so the visual quality of the reconstructed 3D image is degraded. However, these cracked parts can be interpolated from adjacent elemental images. Therefore, in this Letter, we try to improve the visual quality of reconstructed 3D images by interpolating and regenerating virtual elemental images with adjacent elemental images after removing the occlusion layers. To prove our proposed method, we carry out optical experiments and calculate performance metrics such as the mean square error（MSE） and the peak signal-to-noise ratio（PSNR）.