Incisal Bite Research Articles

An in vivo strain-gauge analysis of the squamosal-dentary joint reaction force during mastication and incisal biting in Macaca mulatta and Macaca fascicularis

Rectangular rosette or single-element strain gauges were bonded to surgically-exposed mandibular cortical bone in the region immediately below the temporo-mandibular ligament in adult and sub-adult macaques. After recovery from the general anaesthetic, bone strain was recorded during incision and mastication of apples. The bone strain data demonstrate that the joint is loaded to varying degrees depending on the position of the bite point. Bone strain values were larger on the contralateral side than on the ipsilateral during mastication, demonstrating that the net compressive reaction force along the contralateral joint probably exceeds the net compressive reaction force along the ipsilateral one during these periods. The largest bone strain values were recorded during apple incision, demonstrating that the joint is also loaded during incisal biting.

Incisal bite force direction in humans and the functional significance of mammalian mandibular translation.

AbstractIncisal bite force direction was recorded and analyzed in ten human subjects using a specially designed force transducer. In all ten subjects the maxillary incisal bite force was vertically and anteriorly directed both during static biting and during biting associated with simultaneous mandibular translation and rotation. Since the resultant muscle force could not have been equal and opposite to the mandibular bite force, the mandibular condyles must have been loaded. These data demonstrate that the mandible acts as a lever during incisal biting and that there is no consistent relationship between incisal bite force direction and object size. In some individuals the bite force direction was more vertical during biting on a large transducer (30 mm high), while in other subjects it was more vertical during biting on a small transducer (10 mm high).

Isometric bite force and its relation to dimensions of the facial skeleton

Maximum voluntary isometric bite force was recorded at the incisors and at the molars in 29 healthy females aged 19–23 years. The relationships between the variations in bite force and dimensions of the facial skeleton were studied by means of linear simple and multiple regression analyses.There was a high correlation between incisor and molar bite force. Bite force was mainly associated with a long mandible and a small gonion angle. 49% of the variation in incisor bite force could be explained by variations in the length of the mandible, the gonion angle and the length of the anterior cranial base. 56% of the variation in molar bite force could be explained by variations in the length of the mandible, the gonion angle and a long maxilla.

6 才より 11 才における口腔形質の発育の研究 : 1 口腔形質の男女間の差

Annual growth rates were measured for the dental arch and oral palate through 6 year period of the young subjects ranging in age from 6 to 11. Besides these, other items measured in this study included general physique, head, face, breadth of dental arch and oral palate, height of oral palate, breadth of lower alveolus, length of dental and palatal arches, circumferential length of dental arch, incisor bite degree, and incisor over-bite degree. Comparison was made of the sizes of these anatomical structures among every age groups and between both sexes, and the results were summarized as follows. 1. The difference by sexes in each age stage group with regard to the sizes of the anatomical structures as evaluated by the mean ratios revealed that in the majority of items examined the male groups always showed larger values as compared to the other groups. 2. Of the anatomical structures examined, the male groups exceeded the other groups at every age step particularly in those items such as general physique, breadth of dental arch and oral palate, breadth of lower alveolus and length of dental arch. However, with regard to height of oral palate, no appreciable difference was noted between the male and female groups, and in the point of palatal arch length the female groups showed even larger values than did the male gropus.

下関市、八幡市及び別府市女の歯列弓と口蓋の研究 : 第二編口蓋について

To date rather scanty informations are available in relation to the female subjects in the studies on various anatomical traits of the human mouth, in spite of relative abundance of reports accumulated thereon indifferently of sexes. It is especially so, when it deals with comparison between groups of female subjects in the same range of ages residing in the different sections of land. In view of this, a survey has been conducted on 270 female subjects 17 to 29 years of age residing in Shimonoseki, Yawata and Beppu cities, and, as the control, on 100 male subjects 18 to 28 years of age residing in Shimonoseki city. The data of measurement on the tooth bite, dental arch and palate of the subjects were compared between each regional groups, and at the same time comparison between sexes was done with male and female subjects residing in Shimonoseki city. A TOOTH BITE AND DENTAL ARCH 1) Tooth bite and over-bite degrees in the incisor tooth region : There was no difference in the incisor bite degree between each regional group, nor hardly any between both sexes groups. As to the over-bite degree, that in the female of Shimonoseki was the smallest of all. Also that of the female was smaller than that of the male in Shimonoseki with considerable difference present. 2) Dental arch length : No difference was shown to be present between regional as well as sexes groups. 3) Dental arch breadth : Regionally the female in Beppu city is the largest of all, and between sexes the female is smaller than the male with considerable difference present. 4) Dental arch index : Regionally the female in Shimonoseki is the largest, and between sexes the female is larger than the male with considerable difference present there. 5) Dental arch length : Regionally the female in Shimonoseki city was the largest, and between sexes, the female was smaller than the male in lower jaw with considerable difference present there, but almost no difference was present in upper jaw. 6) Circular length of dental arch : Regionally the female in Shimonoseki was by far the largest, but smaller than the male of the same city, with much difference present between both sexes. B THE PALATE 1) Palate height ; In the anterior palate height, the female in Shimonoseki was larger than that in Yawata, but hardly any difference was there between both sexes groups in Shimonoseki. In the posterior palate height, regional difference was not present. Between sexes, the female was smaller than the male with considerable difference. 2) Palate height index : Regionally compared. the female in Shimonoseki was larger than the female in Yawata in the anterior palate height index, while in the posterior palate height index, the female in Beppu was the smallest of all, and in the antero-posterior palate height index, the female in Yawata was the smallest. Between both sexes, hardly any difference was found in the anterior palate height index, but the female was smaller in the posterior palate height index, larger in the antero-posterior index with considerable difference respectively present there. 3) Length of median palatine suture : Regionally speaking, the female in Shimonoseki was considerably larger than the female in Yawata. There was hardly any difference between both sexes. 4) Length of palatal arch : Regional difference was hardly perceptible, but considerable difference was present between both sexes, the female being smaller than the male in this respect. C In summing up the results of these observations, it was concluded that the data for the dental arch and the palate from the female in Shimonoseki was generally larger than those from the female in other cities examined, and that there seemed no appreciable difference between the female groups of Yawata and Beppu. Comparison between both sexes revealed that the female was larger in the dental arch index and the antero-posterior palate height index, but with regard to the

The influence of four levels of feeding on the position and eruption of incisor teeth in sheep

The distance between the front of the incisor teeth and the front of the maxillary pad (incisor bite measure) was measured in 140 sheep about 1 year old. The sheep consisted of seven breed types—the offspring of Blackface ewes by Wiltshire, Border Leicester, Lincoln and Blackface rams, and of Welsh ewes by Welsh, Wiltshire and Suffolk rams. Within each breed type the effects of four different feeding treatments lasting 7 months were studied. These produced small but very significant differences in bite measure. Differences between breed types were significant only in respect of the division between the two breeds of dam. Effect of breed of dam, however, was confounded with any effect due to differences in origin.The proportion of permanent central incisors which had replaced milk teeth when the animals averaged a little more than a year old was affected both by the level of treatment during the experiment and by breed.

Oral Surgery

The Surgical Correction of Jaw DeformitiesIn children many jaw deformities can be treated by means of orthodontic procedures. Later in life, or if the deformity is severe, surgical correction may give excellent cosmetic and occlusial results. The deformities referred to are mandibular protrusion (prognathism), mandibular retrusion (underdevelopment or micrognathia) and open incisor bite or apertognathia. These deformities are frequently of congenital origin, often inherited (Hapsburg jaw), or acquired through malunion of a fracture, underdevelopment as in early cases of ankylosis or overdevelopment due to such diseases as acromegaly or leontiasis ossea.One of two sites may be selected for . . .