Accuracy of digital jaw relation determination in different occlusal conditions - an in vitro study.

Objectives: In orthodontics, accurate registration of jaw relationships is essential for correct diagnosis and treatment planning. Therefore, accuracy of the digital spatial registration of maxillary and mandibular models and - for the first time-the influence of dentition stage and malocclusion type on this procedure were investigated under controlled conditions.

Materials And Methods: Eight pairs of jaw models, representing different occlusal and developmental statuses (m1-m8), were scanned using two IOS types (PS: Primescan; TR: Trios4).

Trueness of full-arch IO scans estimated based on 3D translational and rotational deviations of single teeth-an in vitro study.

Objectives: To three-dimensionally evaluate deviations of full-arch intraoral (IO) scans from reference desktop scans in terms of translations and rotations of individual teeth and different types of (mal)occlusion.

Materials And Methods: Three resin model pairs reflecting different tooth (mal)positions were mounted in the phantom head of a dental simulation unit and scanned by three dentists and three non-graduate investigators using a confocal laser IO scanner (Trios 3®). The tooth-crown surfaces of the IO scans and reference scans were superimposed by means of best-fit alignment.

Three-dimensional amplitude characteristics of masseter motor units and representativeness of extracted motor unit samples.

Objective: This study aimed to characterize amplitude topographies for masseter motor units (MUs) three-dimensionally, and to assess whether high-density surface electromyography (HDsEMG) is able to detect MU samples that represent the masseter's entire MU pool.

Methods: Ten healthy adult volunteers participated in the study, which combined three EMG techniques. A HDsEMG grid covering the entire masseter, and intramuscular fine-wire electrodes were used to obtain two independent MU samples for comparison.

Comparison of orthodontic measurements on dental plaster casts and 3D scans.

Background And Objectives: Over recent years, we have witnessed a growing trend in orthodontics toward the use of three-dimensional (3D) techniques for diagnostic purposes, treatment planning, and fabricating appliances. This study was undertaken to compare the traditional manual technique of using vernier calipers to take orthodontic measurements on plaster dental casts versus an all-digital measuring technique based on virtual 3D scans of casts. In this study, we focused on the quantitative agreement between and time requirements of both methods.

Electrophysiological method to examine muscle fiber architecture in the upper lip in cleft-lip patients.

Objectives: The upper lip's musculature comprises several muscle fiber groups with different spatial orientations for various lip movements. In the past, it has not been possible to describe these various groups and their motor units in detail with traditional methods of electromyography (EMG). The purpose of this investigation was to create a viable method for studying the architecture of upper-lip muscle fibers in patients with surgically closed cleft lip by refining the design of a flexible electrode array for multichannel EMG.