What Is a Posterior Crossbite?

Bite mark refers to the damage caused by the occlusion of the upper and lower jaw teeth of a human or animal, which can be formed during attack and defense. Due to the differences in the shape of the human dental arch, the arrangement and densification of teeth, and the changes in physiology and pathology, in addition to the effects of changes such as restoration and loss of teeth, the bite marks of teeth have good individual specificity.

bite

Bite concept

Bite mark refers to the damage caused by the occlusion of the upper and lower jaw teeth of a human or animal, which can be formed during attack and defense. Due to the differences in the shape of the human dental arch, the arrangement and densification of teeth, and the changes in physiology and pathology, in addition to the effects of changes such as restoration and loss of teeth, the bite marks of teeth have good individual specificity.

Characteristics of bites

Slight bite marks leave only slight marks on the skin and disappear quickly; heavier bite marks form subcutaneous hemorrhage with abrasions; heavier bites damage the integrity of the skin, forming contusions and even tissues and organs Defects and irregular wounds. More common are round or oval bite marks formed by symmetrical semi-curved tooth marks, which are common on the cheeks, shoulders, and breasts. On the fingers and other protruding parts, such as nipples, noses, ears, etc., bite marks can be distributed on the corresponding bilateral sides in a symmetrical manner. The bite marks formed by the upper and lower jaw teeth are not fused; in severe cases, tissues or organs are partially missing.

The bite marks formed by the teeth and dentition of different parts are different. Under normal circumstances, the maxillary teeth bite is larger and longer than the lower jaw, and the damage is also serious; the maxillary teeth are looser than the lower jaw, the upper maxillary incisor crown is larger, the cut surface is thinner and straighter, forming a relatively long "one" shape Bite marks; the crown of the mandibular central incisor is smaller, the cut surface is also thin and straight, and the length is only 2/3 of the maxillary central incisor, forming a relatively short "one" shaped bite. The incisal edge of the canine is sharper, reflecting a bite mark on the bite mark. The bicuspid teeth form two tooth marks on the buccal and lingual surfaces. Molars have 4 to 5 cusp marks, which are distributed squarely. But usually molars are less likely to form bite marks.

Fixation and extraction of bites

If bites are found, the bite marks should be inspected, fixed, and extracted in time, because some bite marks will quickly deform or disappear.

First, saliva spots on the surface of the bite should be extracted for physical evidence inspection and individual identification. Separate the bite from the clothes. Use ultraviolet light to check the clothes for saliva spots or other invisible marks. The second is to fix the bite marks with a scale. For bite marks on curved skin, take a three-dimensional photo. Once again, the bite marks were collected with gypsum solution, and the mold was restored. If it is a bite on a corpse, the skin of the corresponding part should also be removed and fixed with 10% formalin solution. Finally, if a suspect is found, a suspect tooth model is taken with alginate, rubber, etc. for comparison. To compare the bite marks, first determine the position of the bite mark, the type and position of the jaw, and the characteristics of the bite mark, and then compare and analyze with the suspect dental model in all aspects, so as to make a valid or negative conclusion.