Centric relation: A needed reference position

Digital Workflows in Implant Dentistry Utilizing Intraoperative CT Scanning

Many digital workflows have been utilized in the past few years in the acquisition of implant positions for full arch implant positions intraoperatively and postoperatively. The goal of the different workflows is to offer speed, precision, and predictability. This study outlines the steps for an innovative fully digital full arch workflow that ensures predictable and fast outcomes using digital tools available in most dental implant centers.

Provisional Prosthetic Outcome when Using Photogrammetry for Complete Arch Oral Implants: A Report of 111 Patient Treatments

Complete arch oral implant treatment using photogrammetry was studied in 77 patients with 111 arches focusing on digitization of clinical records and optimization of the provisional. The aim of the study was to test the hypothesis that patient satisfaction with the provisional prosthesis during the first 4 months of care determined workflow efficiency and success. Digitization of 8 clinical records was done including centric relation, vertical dimension, esthetics, occlusion, inter-arch space, abutment selection, abutment capture, and soft tissue scan. These records were then used to manufacture the provisional prostheses. All 111 prostheses seated passively indicating accurate photogrammetry registration.

What occlusal scheme should be used for tooth-supported fixed partial dentures?

PURPOSE

The purpose of this review of occlusion for fixed partial dentures (FPD) placed on natural teeth was to determine the level of scientific evidence available regarding the occlusal scheme during eccentric mandibular movements and the scheme for occlusal contact in the maximal intercuspal position (MIP).

MATERIALS AND METHODS

A PubMed search of "natural teeth, dental occlusion, fixed partial dentures, bridges" using the filters: Case Reports, Clinical Trial, Randomized Controlled Trial, Systematic Review resulted in 7 citations, none of which were relevant. Two were on complete dentures, 2 on implants, and 1 on removable partial dentures. As a result of the literature search and review, it was determined there is a lack of compelling evidence to support a specific eccentric occlusal relationship, tooth form, or how opposing teeth interdigitate, necessitating a look back at First Principles.

RESULTS

Three natural dentition eccentric occlusal relationships have been described in the dental literature: canine protected articulation (CPA), group function (GF), and balanced occlusion. There are no clinical trials focused on the differences between occlusal schemes for occlusal rehabilitation of natural teeth using FPDs. Most clinical studies of natural dentitions determined that GF occurs more commonly than CPA but there is a lack of data supporting the superiority of either of these two eccentric occlusal relationships. There were no clinical studies on occlusal contact schemes with FPDs. Two basic intercuspal schemes have been advocated, cusp-to-fossa and cusp-to-marginal ridge. There is no evidence for how many occlusal contacts are necessary for a stable occlusion with some authors having recommended buccalized or lingualized occlusion.

CONCLUSIONS

With FPD occlusion involving natural teeth, there is no clinical evidence supporting the superiority of one eccentric occlusal relationship over another. During protrusive movements, guidance by only the incisors without posterior tooth contact is the most common type of relationship and it is more common in Angle's Class Type I occlusions than in Angle Class II and III occlusions. Posterior tooth contact can occur during protrusion, and it is most common in Angle Class III occlusions and least common in Angle Class II occlusions. The canines can make occlusal contact during protrusive movements. Clinicians have used both GF and CPA in the restoration of teeth with FPDs. When restoring one arch the prostheses should harmonize with the patient's existing occlusal scheme if no other pathology exists. Nonworking side (mediotrusive) contacts should not be present on posterior teeth during lateral mandibular movements. In MIP, occlusal forces should be directed along the long axis of teeth. Some clinicians prefer that occlusal forces not be present on inclined surfaces in MIP and have cuspal contact on opposing flat fossae whereas others use multiple contacts on inclined surfaces around cusps, a process known as tripodizing. There is no clinical evidence that tripodizing or cuspal contact on flat surfaces enhances positional stability of the teeth or improves masticatory function. There is a need for extensive research of excursive and MIP schemes involving fixed partial dentures attached to natural dentition.

Clinical Dental Midline Shift Is Not a Predictor of the Side of Shorter Hemimandible: A Cone Beam Computed Tomography Diagnostic Study

Background/Objectives: Interincisive midline deviation is frequent. Determining the cause (dental versus skeletal) is crucial for treatment planning. This study assessed the null hypothesis that neither clinical dental midline shift nor the temporomandibular disorder (TMD)-affected side correlate with maxillary/mandibular asymmetry. Methods: Thirty-eight CBCT scans were analyzed: thirty-five (92.1%) females, three (7.9%) males; mean (SD) age 34.6 (11.9) years old. Tomographic images were acquired using the i-CAT® Imaging System; mandibular/maxillary measurements were obtained with the Planmeca Romexis® software v.6.This is an ancillary study of a clinical trial (NCT02144233) that included chronic pain (TMD diagnosis; DC/TMD criteria), fully dentate, and stable normo-occlusion participants. Results: We found sixteen (42.1%) dental midline deviations to the right and thirteen (34.2%) to the left. In the study population, the right side was more developed: a hemimandible length of 119.4 (5.7) mm versus 118.6 (5.3) mm for the right and left sides, respectively (95% CI 0.21 to 1.51), p = 0.01. Conclusions: Neither the dental midline shift side nor the affected side predicted a less developed hemimandible.

Digital trifunctional intraoral appliance for centric relation recording: A dental technique

A technique for fabricating a trifunctional intraoral appliance is described. This appliance streamlines the process of recording centric relation by combining the functions of an anterior deprogrammer, gothic arch tracer, and record base with occlusal rims into a single device. The use of digital tools in this technique offers greater convenience and efficiency compared with conventional methods.

Recording the maxillomandibular relationship with the Aqualizer system prior to occlusal splint therapy for treating temporomandibular disorders: a randomized controlled trial

Temporomandibular disorders (TMD) present a public health issue and are one of the most common musculoskeletal conditions causing chronic pain. This study compares the outcomes of occlusal splint therapy in patients with TMD following two different maxillomandibular relationship (MMR) registration techniques. 40 TMD patients were randomly allocated to MMR registration with the Aqualizer system (AQU) or with chin point guidance (CPG) prior to fabricating occlusal splints. TMD symptoms, subjective pain intensity, and quality of life (QoL) were recorded at baseline and after 3 and 6 months. The treatment led to an overall reduction of TMD symptoms in both groups (Conover test, p < 0.00001). TMJ sounds, TMJ pain with palpation and muscle pain with palpation subsided regardless of the type of MMR registration method used (Cohen's d > 0.8). AQU-based occlusal splints led to a better improvement of TMJ pain with maximum opening compared to CPG-based occlusal splints (Cohen's d = 0.9; CPG d = 0.13). In both groups, occlusal splint treatment had little to no effect on correcting lateral mandible deviation or improving restricted jaw opening. After 6 months occlusal splints in both groups had a large effect on improving subjective pain intensity (Cohen's d > 0.8), however, patients reported a higher QoL in the AQU group compared to the CPG group (Mann-Whitney-U-test, p < 0.05). The results of this study support the premise that occlusal splints are effective in relieving pain-related TMD symptoms. The Aqualizer can be considered for determining MMR in cases, where guided registration techniques are not possible.Trial registration: DRKS00031998.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2022 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertise in their subject areas that include (in order of the appearance in this report): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence the daily dental treatment decisions of the reader with an emphasis on innovations, new materials and processes, and future trends in dentistry. With the tremendous volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope that readers find this work helpful in managing patients.