Faculty Bibliography

PURPOSE/OBJECTIVE:Complications can and do occur with implants and their restorations with causes having been proposed for some single implant complications but not for others. METHODS:A review of pertinent literature was conducted. A PubMed search of vibration, movement, and dentistry had 175 citations, while stress waves, movement, and dentistry had zero citations as did stress waves, movement. This paper discusses the physics of vibration, elastic and inelastic collision, and stress waves as potentially causative factors related to clinical complications. RESULTS:Multiple potential causes for interproximal contact loss have been presented, but it has not been fully understood. Likewise, theories have been suggested regarding the intrusion of natural teeth when they are connected to an implant as part of a fixed partial denture as well as intrusion when a tooth is located between adjacent implants, but the process of intrusion, and resultant extrusion, is not fully understood. A third complication with single implants and their crowns is abutment screw loosening with several of the clinical characteristics having been discussed but without determining the underlying process(es). CONCLUSIONS:Interproximal contact loss, natural tooth intrusion, and abutment screw loosening are common complications that occur with implant retained restorations. Occlusion is a significant confounding variable. The hypothesis is that vibration, or possibly stress waves, generated from occlusal impact forces on implant crowns and transmitted to adjacent teeth, are the causative factors in these events. Since occlusion appears to play a role in these complications, it is recommended that occlusal contacts provide centralized stability on implant crowns and not be located on any inclined surfaces that transmit lateral forces that could be transmitted to an adjacent tooth and cause interproximal contact loss or intrusion. The intensity, form, and location of proximal contacts between a natural tooth located between adjacent single implant crowns seem to play a role in the intrusion of the natural tooth. Currently, there is a lack of information about the underlying mechanisms related to these occurrences and research is needed to define any confounding variables.

Three-dimensional (3D) metrology software programs were designed to allow the user to capture and process the data from 3D scanners and other devices to measure, understand, and communicate inspection results to ensure manufacturing quality. Its use in dentistry has increased with concerns over how to make clinically significant decisions based on the data provided. The data produced by a commonly used software program was reviewed, and a rationale for interpreting that data was presented. The requirements for trueness, precision, and tolerance were also reviewed. In addition, contact was made with Oqton Tech Support, who is responsible for the Geomagic software program. The arithmetic average and the root mean square (RMS) do not identify the amount of deviation nor the direction and may not be helpful in determining how to use the data. RMS, and other statistical approaches, can show that there was a deviation but do not tell how much and in what direction. For prosthodontic studies, the 3D color map is the most efficacious method of determining the clinical significance of 3D metrology software.

PURPOSE/OBJECTIVE:Centric relation (CR) is a universally recognized term and an acceptable reference position with a long history of success. The problem is that there is little consensus as to its definition or the method of recording it, and this has created an uprising to abolish it. METHODS:A review of pertinent literature related to its definition, method of recording, anatomic considerations, and long-standing principles was conducted. RESULTS:Centric relation is an established term but there are valid concerns over its definition and method of recording. There is consensus on using it as a restorative position in a patient in need of full-arch reconstruction, and there is no substantive clinical research to contradict this. If a clinician decides to use a different position, it should have a different name. CONCLUSIONS:Centric relation is a reproducible reference position that can be utilized for diagnostic and restorative dental procedures with substantial scientific evidence to support that premise. There are numerous well-documented techniques, all of which are intermaxillary, that can replicate the position. There is little scientific evidence to support a premise as to where the exact position of the condyle should be in relation to the fossa.

The ever-expanding world of digital technology has produced many changes, including the availability of virtual articulators. The use of such digital technology requires an understanding of the features that have been available with different mechanical articulators. These features include such items as facebow, intercondylar distance, incisal guide table, condylar inclination, reference plane, lateral condylar inclination, immediate mandibular translation, and ability to verify a centric relation record. This paper reviews the adjustable features that have been available with different types of mechanical articulators so that clinicians can determine if these features should be included in the virtual articulators they choose to use. Regardless of whether one is utilizing a mechanical or virtual articulator, the rationale for which type of articulator to select is the same and is predicated on the needs of the patient, the occlusal philosophy of the clinician, and the required accuracy.

PURPOSE/OBJECTIVE:In a series of publications, Dahl and Krogstad promoted an orthodontic technique for the treatment of severe wear of the anterior teeth that reportedly could induce intrusion of the anteriors and extrusion of the posterior teeth to allow space to restore the worn anterior teeth. The purpose of this Best Evidence Consensus Statement was to evaluate the existing dental literature related to the Dahl Concept. METHODS:A PubMed search limited to clinical studies, clinical trials, randomized controlled trials, systematic reviews, meta analyses, and journal articles, using the key words Orthodontics, Dahl appliance, Dahl concept and adult, revealed 11 citations, 9 of which were related. An additional 9 citations were culled from the reference lists in the aforementioned articles. RESULTS:The 20 articles that met the initial search criteria were evaluated and rated. The literature largely focused on the restorative materials that are commonly used to apply the Dahl technique. CONCLUSIONS:While there is low-level evidence from a few case series that demonstrated the ability to achieve enough space in the anterior region for the restoration of lost anterior tooth structure, there is no compelling evidence to support any theories as to how that space was achieved. In addition, there is no evidence to support the long-term stability of that position and the restorations. Negative position and restorative outcomes have been reported.

The inability to place a sufficient number of implants posteriorly may limit tooth and soft tissue replacement because of the cantilever effects that would result from the unsupported prosthesis. Fabrication of a fixed removable overdenture that is implant retained and supported by both implants and soft tissue allows adequate replacement of teeth and soft tissue for optimal mastication and esthetics. This case report describes a design for implant overdentures that conforms to fundamental removable prosthetic principles by using a rigid bar with bilateral locking passive attachments. The rigid implant overdenture provides extra retention via the locking attachments while maintaining stability with proper extensions and full soft tissue support posteriorly. This removable implant overdenture design is a suitable treatment option for patients who desire the sensation of a fixed prosthesis but are unable to receive fully implant-supported prostheses.

Analysis of microbe diversity in freshwater resources and nearshore seawater samples of Upolu Island was performed to investigate the distribution of harmful bacteria. For this, 124 samples were collected from 23 river systems, two volcanic lakes, and 45 locations inside and outside the barrier reef of Upolu Island, Samoa. Physicochemical parameters for general water quality, detection of coliform bacteria and 16S rRNA amplicon sequencing were performed on all samples. Fecal indicator bacteria (FIB) testing indicated a wide distribution of coliform bacteria in all sampled freshwater sites with evidence of fecal coliform in most locations. Importantly, evidence of coliform bacteria was found in most seawater samples inside and along the reef, apart from those samples taken ~20 km offshore. Illumina 16S rRNA amplicon sequencing of the V4 hypervariable region confirmed the presence of various types of harmful bacterial species, namely from the Enterobacteriaceae, Enterococcae, Streptococcaceae, and Vibrionacea families. By combining the sensitivity of FIB testing and next-generation sequencing, we were able to show the extent of potential contaminations in fresh and seawater samples and simultaneously identify the potential pathogenic bacterial genera present. The wide distribution of potential harmful bacteria from river runoff or direct sewage dumping has an impact on human health, leading to many skin and intestinal diseases, and is potentially detrimental to coral reef community health.

Growth factor and chemotherapy-based stem cell mobilization strategies are commonly used for patients with multiple myeloma. We retrospectively compared 398 patients mobilized between 2017-2020 using either cyclophosphamide (4g/m²) plus granulocyte colony stimulating factor (GCSF) or G-CSF alone, with on demand plerixafor (PXF) in both groups. While total CD34⁺ yield was higher after chemo-mobilization compared to GCSF+/-PXF (median 13.6 vs. 4.4 × 10⁶/kg, P< .01), achievement of ≥ 2 × 10⁶ CD34⁺ cells (95% vs 93.7%, P= .61), and rates of mobilization failure (5% vs. 6.3%, P= .61) were similar. Fewer patients required PXF with chemo-mobilization (12.3% vs 49.5%, P< .01), and apheresis sessions were fewer (median: 1, range 1-4 vs. 2, range 1-5). Complications were higher after chemo-mobilization (30% vs. 7.4%, P< .01), including neutropenic fever, ED visits, and hospitalizations. Prior lenalidomide ≤6 cycles did not impair cell yield in either group. Median cost of mobilization was 17.4% lower in the GCSF +/- PXF group (P= .01). Differences in time to engraftment were not clinically significant. Given similar rates mobilization success, engraftment time, and less toxicity and lower costs compared to chemo-mobilization, G-CSF with on-demand PXF may be preferable in myeloma patients with adequate disease control and limited lenalidomide exposure.

PURPOSE/OBJECTIVE:This Best Evidence Consensus Statement evaluated the existing Angle's classification clinical literature to determine if the Angle's classification as historically determined in maximum intercuspal position (MIP) with hand held casts is coincident with the centric occlusion (CO) determined Angle's classification. In addition, it explored the value of using Angle's classification for edentulous patients MATERIALS AND METHODS: The search strategy was related to the focus questions and limited to Meta-analyses, Systematic Reviews (SR), Randomized Controlled Trials (RCT) and Clinical Trials. Searches were completed using the term Angle's classification and Boolean Modifiers (AND) with the key terms: dental occlusion, dental occlusion centric, centric occlusion, centric relation, maximal intercuspation, MIP, intercuspal position, and edentulous patient, retrognathia, determination, and prognathia. Additional related articles were culled from the reference lists in the articles found in the PubMed searches. RESULTS:The search identified 494 articles related to the selected terminology. Titles were reviewed and selected if related to the focus questions for further review. Seven papers could be identified that addressed the specifics of the questions. CONCLUSIONS:There is evidence that the Angle's classification for many patients will change when recorded in CO compared to the historical MIP determination/definition. A different Angle's classification recorded in CO is potentially a significant diagnostic finding for patients needing complete mouth rehabilitation. The current definitions of Angle's Classification are not useful in the management of edentulous patients.