Validation of a new domiciliary diagnosis device for automatic diagnosis of patients with clinical suspicion of OSA.

BACKGROUND AND OBJECTIVE: Obstructive sleep apnoea is a prevalent and considerably underdiagnosed disease. The development of cost-effective, home-based, automatic diagnostic devices to improve the diagnosis accessibility is therefore essential. METHODS: In this study, a new portable polygraph (BTI-APNiA) was used to validate automatic scoring. This five-channel device records respiratory flow, oxygen saturation, heart rate, body position and snoring. The validation was performed in two phases. In the first phase, manual and automatic scorings of a new respiratory polygraphy (RP) device (BTI-APNiA) were compared. In the second phase, automatic analysis performed with BTI-APNiA was compared with manual scoring of a validated RP device (Embletta Gold). RESULTS: Phase I was completed by 424 patients (50.5% males, 52.2 ± 12.4 years, BMI of 25.4 ± 4.8 kg/m2 and Epworth Sleepiness Scale score of 8.0 ± 4.0). Manual and automatic analysis resulted in an apnoea-hypopnoea index (AHI) of 13.7 ± 12.7 and 14.0 ± 12.5 (P > 0.05), respectively. The interclass correlation coefficient (ICC) was 0.99 (P < 0.001). During Phase II, 28 patients were evaluated (72.0% men, 49.1 ± 10.9 years, BMI of 27.1 ± 4.2 kg/m2 and Epworth Sleepiness Scale score of 7.5 ± 4.2). Manual analysis of Embletta Gold recordings indicated an AHI of 12.3 ± 14.0, while automatic analysis of the BTI-APNiA was 13.4 ± 14.7 (P > 0.05). The ICC was 0.68 (P < 0.01). CONCLUSION: The automatic analysis of the BTI-APNiA is as accurate as manual analysis of AHI. This automatic analysis compared well with the manual analysis of a validated RP device (Embletta Gold).

Implant-Supported Prostheses in the Edentulous Mandible: Biomechanical Analysis of Different Implant Configurations via Finite Element Analysis.

This study explores the implant-supported prosthetic treatment alternatives of the edentulous mandible from a biomechanical point of view by means of a Finite Element Analysis (FEA). Finite element (FE) models were used to simulate cases treated with six, five, and four, implants and a fixed prosthesis with a cantilever. In the four implant treatments, three cases were analyzed; the posterior implants were placed in axial positions, angled at 30° and 45°. Cases with six and four axially placed implants were also analyzed by placing the posterior implants distally to the foramen, thus eliminating the cantilever in the prostheses. In the cases with implants between foramina, the highest values for the principal strains and von Mises stresses were observed in the case with four implants where the posterior implants were angled at 45°. Cases with implants placed distally to the foramen and without a cantilever showed much lower bone stress and strain levels compared to cases with implants between foramina. From a biomechanical point of view, it seems to be a better option to use implants positioned distally to the foramen, eliminating cantilevers.

Influence of Implant Tilting and Length on the Biomechanics of Single-Tooth Restoration: A Finite Element Analysis in Atrophic Mandible.

The aim of the present study is to assess by means of finite element models the effect on bone stresses of implant length and tilting in single-unit implant restorations. The factors that were analyzed in this study were implant length (4.5, 5.5, and 10 mm), implant titling (0, 17°, 30°, and 45°), bone type (0/I, II, and III), and loading (immediate and delayed). An axial load of 200 N was applied to the occlusal surface of the prosthesis at a height of 11 mm and the Von Mises equivalent stress in the bone was analyzed. Finite element analysis indicated that the most determinant factor was implant tilting. Tilting the implant by 17° doubled the Von Mises stress received by bone. The highest increase was in the case of implant tilting at 45° (by 1300%). The use of extra-short implants did not produce a significant increase in Von Mises stress in bone. Moreover, the length of the implant did not affect the stress value in bone types I and II. Based on the obtained results, an axially placed short implant would be a better option than titling a standard-length implant to support a crown restoration in an atrophic mandible from a biomechanical point of view.

Influence of Dental Implant Diameter and Bone Quality on the Biomechanics of Single-Crown Restoration. A Finite Element Analysis.

BACKGROUND: Success of an implant-supported prosthesis is highly dependent on implant diameter and bone quality. The objective of this study is to assess these two variables under axial or 30° angulated loading. METHODS: The study was conducted using finite element model simulations of dental implants with an unchanging length of 6.5 mm and varying diameters of Ø3.3; Ø3.5; Ø3.75; Ø4, Ø4.25 and Ø4.75 mm. The implants were placed in an axial position and a 2 mm high straight transepithelial (intermediate abutment) was used to perform a single tooth restoration. Four bone quality scenarios, Type IV, III, II or 0-I bone, were simulated from a simplified model of the mandible. A 200N load was applied both axially and at a 30° angle to the occlusal surface of the prosthesis, which was 11 mm above the implant platform, and the equivalent Von Mises stress in the bone was analyzed. RESULTS: The maximum stress value was obtained for the Ø3.3 implant in Type IV bone (235 MPa), while the lowest value was obtained for the Ø4.75 implant and in Type 0-I bone (41 MPa). Regardless of the implant diameter, an improvement in bone quality produced a reduction in bone stress. The same effect was observed as the implant diameter was increased, being this effect even more pronounced. CONCLUSIONS: Implant diameter has an important effect on bone stress, with a reduction in stress as the implant diameter increases.