An In-Vitro Evaluation of Articulation Accuracy for Digitally Milled Models vs. Conventional Gypsum Casts

With the advent of a digital workflow in dentistry, the inter-occlusal articulation of digital models is now possible through various means. The Cadent iTero intraoral scanner uses a buccal scan in maximum intercuspation to record the maxillomandibular relationship. This in-vitro study compares the occlusion derived from conventionally articulated stone casts versus that of digitally articulated quadrant milled models. Thirty sets of stone casts poured from full arch polyvinyl siloxane impressions (Group A) and thirty sets of polyurethane quadrant models milled from digital impressions (Group B) were used for this study. The full arch stone casts were hand-articulated and mounted on semi-adjustable articulators, while the digitally derived models were pre-mounted from the milling center based on the data obtained from the buccal scanning procedure. A T-scan sensor was used to obtain a bite registration from each set of models in both groups. The T-scan data derived from groups A and B were compared to that from the master model to evaluate the reproducibility of the occlusion in the two groups. A statistically significant difference of the contact region surface area was found on #11 of the digitally articulated models compared to the master. An analysis of the force distribution also showed a tendency for a heavier distribution on the more anterior #11 tooth for the digitally articulated models. Within the limitations of this study, the use of a digitally articulated quadrant model system may result in a loss of accuracy, in terms of occlusion, the further anteriorly the tooth to be restored is located. Care must be taken to consider the sources of inaccuracies in the digital workflow to minimize them for a more efficient and effective restorative process.

Keeping Teachers Afloat with Instructional Coaching: Coaching Structure and Implementation

Despite the press for instructional coaching as a form of effective teacher professional development (TPD), there is still a need to understand what instructional coaching is and how its operations look like. Meanwhile, the coaching literature provides scant guidance particularly about the coaching implementation in the Malaysian context. For the purpose of this study, we explored the processes of instructional coaching in Sarawak, particularly focusing on conceptualising the coaching processes to fine-tune teaching practice. Employing a qualitative case study design, we conducted non-participant observations on coaching conferences of four coach-teacher pairs on a one-to-one basis. We analysed the data obtained using Braun and Clarke’s (2006) six-phase thematic analysis. The findings suggested that the coaching cycle consisted of three stages: pre-observation conference, classroom observation and post-observation conference. An additional stage of intervention was identified in the coaching cycle. Coaching support to the teachers was provided on an average of one session per month. Structuring coaching conversations was a key aspect in conducting coaching support for the teachers. For future research, we offer recommendations of larger-scale studies to discover the impact of instructional coaches that include the intervention component as a part of the coaching cycle to enhance teacher instruction and student achievement. We would also suggest studies based on comprehensive theories and empirical evidences into the development of fully articulated models of instructional coaching related to the Malaysian context.