Registration of the Seated Condylar Position (SCP/CR): Part II: Technique: The Two-Piece Wax Bite Registration

The purpose of this paper is to present the technique for registration of the Seated Condylar Position (SCP)/Centric Relation (CR) position of the condyles: a two-piece wax bite registration with deprogramming and no mandibular manipulation.

Registration of the Seated Condylar Position (SCP/CR): Part I: Rationale

The purpose of this paper is to present the rationale for registration of the Seated Condylar Position (SCP)/Centric Relation (CR) position of the condyles.

Articulated dental cast analysis of asymptomatic and symptomatic populations

Dental instrumentation has long provided insight into the mechanism of musculo-skeletal function of the gnathic system. While large population studies associate dental arch displacement （DAD）, especially laterally, with symptoms, mandibular condyle displacement （CD） resulting from DAD has not been targeted as possibly etiologic in the production of common muscle contraction headache （CMCH） and temporo-mandibular dysfunction （TMD）. The objective was to evaluate the three-dimensional nature of DAD and CD between the seated condylar position （SCP） and the intercuspal position （ICP） and to compare results derived from large deprogrammed asymptomatic and symptomatic populations. A total of 1 192 sets of dental casts collected from asymptomatic and symptomatic populations were articulated in the SCP. The initial occlusal contact, DAD, and condylar displacement were evaluated for frequency, direction, and magnitude of displacement between the SCP and ICP. The data revealed significant displacement between the SCP and ICP of the condyles （displaced most frequently inferior （down） and posterior （distal）） and substantially increased frequency and magnitude of displacement of the dental arches （with posterior premature occlusal contacts, increased overjet, decreased overbite, midline differences, and occlusal classification changes） in symptomatic subjects. These discrepancies were statistically significant and clinically significant. The data support the concept of increased DAD and CD with dysfunction. Transverse condylar displacement, commonly presenting with dental cross bite, may be associated with CMCH and TMD. Displacement of the mandibular condyle may be an etiologic factor in CMCH and dysfunction of the temporo-mandibular joint.

Evaluation of differences in injury patterns according to seat position in trauma victims survived traffic accidents

Purpose： Investigation of injury patterns epidemiology among car occupants may help to develop different therapeutic approach according to the seat position. The aim of the study was to evaluate and compare differences in the incidence of serious injuries, between occupants in different locations in private cars. Methods： A retrospective study including trauma patients who were involved in motor vehicle accidents and admitted alive to 20 hospitals （6 level I trauma centers and 14 level II trauma centers）. We examined the incidence of injures with abbreviated injury score 3 and more, and compared their occurrence be- tween seat locations. Results： The study included 28,653 trauma patients, drivers account for 60.8% （17,417）. Front passenger mortality was 0.47% higher than in drivers. Rear seat passengers were at greater risk （10.26%） for trau- matic brain injuries than front seat passengers （7.48%） and drivers （7.01%）. Drivers are less likely to suffer from serious abdominal injuries （3.84%） compared to the passengers （front passengers - 5.91%, rear passengers - 5.46%）. Conclusion： Out of victims who arrived alive to the hospital, highest mortality was found in front seat passengers. The rate of serious chest injuries was higher as well. Rear seat passengers are at greater risk for serious traumatic brain injuries. All passengers have a greater incidence of abdominal injuries. These findings need to be addressed in order to develop ＂customized＂ therapeutic policy in trauma victims.