Journal of Dental Medicine

Normal 0 false false false EN-US X-NONE AR-SA Identifying the shades is difficult and needs not only the science but also the art. In order to match and coordinate the shades, distinguishing them is essential. As well as hue, chroma and value, Maverick stains are also considered. Various factors effect color perception such as the difference between the eyes' vision, age, drugs and psychology of the colors. Surface texture is considerably important in adjusting teeth color. Color is the light reflected from teeth structures and is accompanied with scattered photons. Thus, to achieve exact and acceptable results, it is better to use light sources with wide light emission field.

Normal 0 false false false EN-US X-NONE AR-SA People are generally familiar with temporomandibular joint sounds and consider them as normal sounds that rarely needs treatment while unbalanced occlusion is one of the most important risk factors of TMJ disorder.TMD can cause Burning sensation in tongue and throat, tinnitus and pain.  Unlike the other joints in the body, temporomandibular joint has avascular and fibrous articular interface in both sides. Joint sounds can be developed in one or both side in forms of clicking or grinding while at the beginning or at the end of mouth opening as well as at the beginning, in the middle or at the end of mouth closure. The recommended treatments involve occlusion therapy, psychotherapy, physiotherapy and medications.

Normal 0 false false false EN-US X-NONE AR-SA Crown retention is related to its adaptation with tooth while there is always a gap between the crown and prepared tooth. Although this gap is filled with cements but the mechanical retention between axial walls and internal surfaces is decreased. Therefore, what is the relation between die spacer and crown retention? Does it affect retention? And if so, what is the best thickness of it? It has been a long time that various techniques are recommended and used to improve the adaptation of crowns. According to Fusayama and based on some other researches, it can be concluded that by using die spacer we can noticeably decrease the thickness of cement and improve the adaptation of cement. In addition, many studies on thickness and amount of die spacer concluded that by using die spacers, in %55 of cases crown retention was increased while in 30% decreased and 10-15% have not changed. Hence, it seems that using die spacer is generally beneficial and the best thickness of it according to our research is 2-4 layers that can improve retention by 41%.