●齿颚矫正的迷思~6 buccal corridor(颊齿间隙)
6)buccal corridor(=Lateral Negative Space “LNS”)颊齿间隙
~~图里的((B-A) / B )buccal corridor
在**里对buccal corridor width有着以下的定义:
buccal corridor width (buk? l kor?id r),
n the negative space between the buccal surface of the maxillary first premolar and the inner point at which the lips join when the patient smiles. It is often stated as a ratio of the inner lip commissure width divided by the distance between the first maxillary premolars.
The smile and buccal corridors (Dr. Burstone reviewed a number of photos to make the following points).
1. Buccal corridors are very prevalent in the smiles of actors and actresses.
2. Their size depends on the amount (width) of the smile.
3. Their size depends on how the photograph is taken or the view of the face.
4. Their size depends on the amount of mandibular opening.
5. The width of the dental arches is on
The battle for the skeletal modification of the face – maxillary orthopedics
1. Dr. Burstone cited a study by Tanne et al. which showed the treatment effects of maxillary protraction headgear are largely dental with clockwise rotation of the mandible. Tanne K, Sakuda M. Biomechanical and clinical changes of the craniofacial complex from orthopedic maxillary protraction. Angle Orthod. 1991 Summer;61(2):145-52.
2. Dr. Burstone also discussed a case report of maxillary protraction using an implant as anchorage for the protraction. The results showed improvement in lip posture. Cephalometric evaluation showed lingual inclination of the lower incisors from the effect of the chin cap and clockwise rotation of the mandible. No maxillary skeletal effect was seen.
Why is evidenced-based treatment not practiced?
1. Traditions, emotions, beliefs, commercialism, gurus, easy-learning, appliance worship all contribute to the lack of evidenced-based treatment in our specialty.
2. In research, evidence is clouded by sampling methods, traditions, and tendencies to follow authority figures.
3. Epidemiologic da
Buccal corridor refers to the dark space (negative space) visible during smile formation between the corners of the mouth and the cheek-side surfaces of the upper teeth.(嘴角与上排牙齿的颊侧面之间所呈现的阴影部份)
Its appearance is influenced by:(它会受到以下的因素而显现不同的情形)
1. the width of the smile and the upper arch. (微笑的宽度与上颚牙弓)
2. the tone of the facial muscles. (颜面肌肉的张力)
3. the positioning of the labial surfaces of the upper premolars. (上颚小臼齿唇侧面的位置)
4. the prominence of the canines, particularly toward the back of the tooth. (犬齿的突度,尤其是与后面牙齿相比较)
5. any discrepancy between the value (brightness) of the premolars and the six front teeth. (任何与前面6颗前牙与小臼齿明亮度的差异)
Arch form (牙弓型态)has a direct influence on the buccal corridor(会直接影响颊齿间隙). The ideal arch is broad and conforms to a U shape.(理想的牙弓是一U型的形状) A narrow arch is generally unattractive(窄的牙弓通常较不具吸引力). It disrupts the principles of golden proportion(黄金比例) and makes the centrals appear far too dominant.
Patients with very narrow arches(窄的牙弓) may require orthodontics and possibly surgical intervention prior to restoration in order to achieve excellent results. The unattractive, negative space should be kept to a minimum. This problem can be solved or minimized by restoring the premolars. The buccal corridor should not be eliminated completely because a hint of negative space imparts to the smile a suggestion of depth.
The negative space is often accentuated when on
Three smile styles. A. Cuspid. B. Complex. C. Mona Lisa.