Cusp Of Carabelli- Ancestry, Ethnic Association, Native American, Mandibular Molar

A cusp is an elevation of the surface of the tooth, we can see on the top portion of the teeth, which we use to bite or is the primary biting area. Our teeth have different types of the cusp. On the canine teeth, we can find only one cusp, and on the premolars teeth, we can see two cusps.  Moving to the molar teeth segment, each will have four cusps, and in some rare condition, we can find five cusps.

Before we look further to cusps, let us have a fair understanding of teeth and what are their functions.  Apart from other organs of the mouth, teeth play an important role in our eating process. On the teeth, we can find different types of the cusp, such as canines, premolars, and molars. Besides, each tooth has crowns, gum line, root, enamel, dentin, and pulp.

Each type of teeth has different functions to do.

  • Incisors: These teeth usually are chisel-shaped, sharp front teeth come in four upper and lower designed to cut the food.
  • Canines: It is also called as cuspids since it has cusps, which are like small cusps (points) positioned perpendicularly from the surface of the teeth designed to tear and hold the food.
  • Premolars: These teeth are also called as bicuspids because it has two cusps (points) positioned from the surface of the teeth, which helps to bite the food.
  • Molars: These types of teeth will have four or more cusps, positioned from the surface of the biting area of teeth, helps to chew and grind the food.

The cusp of Carabelli is a dental abnormality, which has no utility value or importance, a type of mini cusp development appear on the upper permanent first molars.  It has seen on inside facing side of the teeth seems like an extra bump on the tooth, formed on the Mesiopalatal cusp. The cusp of Carabelli is something similar, however, this one we can attribute to hereditary and is much more uncommon than your regular cusp.

This dental abnormality was first discovered in the year 1842 by Georg Carabelli, an Austrian dentist who was also the dentist of the Austrian Emperor Franz. The cusp of Carabelli, often referred as Carabelli’s tubercle is located as a bulge on the outside surface of the upper morals and as already stated above, are rare. Commonly, this Cusp of Carabelli is found on the people of European descents, so much so that around 85% of individuals possess this cusp.

Cusp of Carabelli ancestry

When it comes to descent, most of those skeletal features are not developed until the person reaches puberty. And the same is true for the cusp of Carabelli in most of the cases. The cusp as already mentioned before is very common in Caucasian people with the percentage ranging from 75 to 85%. However, this ratio is much lower in people of the Pacific Islands, which is around 30 to 40%. Some Japanese skeletons of Jomon period have also found to have these cusps in high numbers.

Carabelli’s cusp Native American

The Native American people are known for their distinctive dental characteristics. Although we could not find the Carabelli cusps in their descendants, there is something else which is quite common, the shovel tooth; which is another dental anomaly. A shovel-shaped tooth is also very commonly found in Asians, but not found in European or African descents. Shovel tooth characteristic happens where the roots are twice the size of the tooth. The tooth has a raised appearance and is concave on the backside and thinner in look. The tooth also usually contains ridges.

Cusp of Carabelli ethnicity

Heredity is passing from one generation to another with some distinct characteristics. There are mostly two types of cusps – positive and the negative cusp. The ethnicity of an individual definitely determines the occurrence of the cusp. It is most rampant in European people, whereas it can sometimes also find in the African and Indian population. It has least seen in the Arctic population. Usually, the cusp is not a significant threat. However, the grooves surrounding the cusps are quite susceptible to decay and should be taken care of as this may lead to dental problems.

The presence of cusp of Carabelli in people has studied for over 150 years. The primary function of the cusp is unknown but assumes that it makes up for the reduction in dental size. Some researchers also believe that it provides the upper molar with higher protection against the biomechanical stress. Sexual dimorphism or the difference of the presence of specific characteristics in male and female gender has not entirely proved in the case of the cusp of Carabelli, which means the presence of the cusp is not more prevalent in any one of the genders. However, the men have seemed to possess this cusp more, but it could also be the result of random sampling in the majority of the studies.

Some researchers also claim that the occurrence of this cusp is dependent on the size of morals of a person. Chinese people usually have little morals and hence a lower frequency of this cusp seen in their case.

Ethnic association of cusp of Carabelli trait and shoveling trait in an Indian population

The study proves that there is an ethnic association between the cusp of Carabelli and shoveling trait in the samples of Indian population belongs to the Dravidian race in the city of Bangalore in Karnataka, India. This study had approved by the Joint Research and Ethics Committee of the Syamala Reddy Dental College of Bangalore, and they had the permission of all the 1953 clinical objects. Of the total number of casts taken, only 1885 casts had selected for the study. The remaining 68 casts rejected due to fractured tooth or restoration on the same.

A cross-sectional study had taken place on children aged between 7 to 10 years. 48.6% of this population were male, while the rest were female.  The presence of cusp of Carabelli in first molar and shoveling tooth in central incisor was studied. The linear regression process used to evaluate the connotation of the cusp of Carabelli, whereas to assess the association of shovel tooth, logical regression used.  The level of statistical significance was fixed at a rate of p<0.05.

The result of the study showed that 40.5% of the children got cusp of Carabelli on their first molar and 68.2% of them on their upper central incisor had shoveling. The study concluded that there was an affirmative association between this two traits-cusp of Carabelli and shovel tooth. However, not many studies have been conducted to comprehend the presence of these two characteristics and this field of study has been largely unexplored.

The one that has done is very crucial in defining the ancestral roots and their association at this time and age. The observation of this study conforms with two other similar studies that had earlier conducted in China. Also, even though Bangalore is a big city with people all over India migrating there and making it their home, the study was strictly restricted to those individuals who were native residents of the city.

Instead of a simple percentage agreement, kappa statistics were used to measure the result of the study. Precisely, kappa statistics are much reliable method than the average percentage method. The same was found to be 0.95 which implies a high degree of agreement in the examination. As already mentioned above, two similar studies have been conducted in China. The study results therein showed that shovel tooth was common in people of Native American, Chinese, Taiwan, Eskimos, and Australian aboriginal descents. Whereas Carabelli cusps were very rare among Native American, Chinese, Taiwan, Eskimos and Australian indigenous ancestries.

Talon cusp

Talon cusps are very rarely found odontogenic anomaly among humans. It is an extra cusp located on the crown of the frontal tooth. This cusp is also commonly known as the supernumerary cusp, interstitial cusp, tuberculated premolar or the eagle’s talon. Talon cusps can create problems in esthetic appearance, occlusal accommodation and thwarting of caries in patients. It will also lead to diagnosis problems for the dentist and clinical management.

Hence the same should be treated with care, and it is crucial that the dentist knows the talon cusp before its outbreak so that it is not mistaken for a supernumerary tooth. Knowledge about the situation is vital as the maxillary incisor region, where it occurs is also a common region for the occurrence of the supernumerary tooth. Also, since the presence of this cusp requires that definitive treatment needed to start, it creates a clinical problem for the dentists as well, rather than it just being considered as a matter of dental foible.

Talon cusp was first discovered in the year 1982 by W.H Mitchell and subsequently named by Louis W. Ripa and J. Kimball Mellor. This cusp as already described above is very rare, and it affects around 1 to 6 % of the population.  It also occurs only on the permanent tooth and very infrequently found in the baby tooth. The researchers have suggested that this anomaly generally occurs due to an evagination.

The talon cusp should be treated immediately and carefully because once it grows, it can affect the person’s oral health and dental hygiene. Depending on the severity of the problem, it can show various physical signs exhibiting a three-pronged look, which is quite similar to an eagle talon. The cusp usually only contains pulp tissues. A pulp tissue is composed of living connective cells and tissues, called the odontoblasts. When seen from the occlusal surface, the talon cusps have an X shaped or a conical appearance.

Talon cusp is large enough to be recognized by a naked eye, though it varies in size, shape, structure, and location. Radiograph and X- rays can also confirm the presence of the same. Though the cause of the occurrence of the cusp is mostly unknown, its prevention is not possible because these occur when the tooth is developing.

Conclusion

More than any other body and facial feature, teeth are much helpful in determining your ancestry. Some of the dental features are more common in one race than the other. The best part is that the teeth can preserve in almost perfect condition for a long time, and hence can be studied easily. This type of study is important when it comes to tracing a person’s roots. They are an excellent source of information to understand the ethnic group of a person.

Since we know through various studies that Cusp of Carabelli is common in European descents and shoveling is common in Native Americans, it plays an important role to determine the race of a person. Cusp of Carabelli is, in fact, one of the most studied dental traits. Mostly found on first molars, its frequency decrease on the second and the third molar. It has asymmetric and bilateral character.

By reading all the above information, we can find that the presence of cusp of Carabelli in primary dentition is a scarce issue.  Probably it might not have noticed until you diagnose it for some reason.  These types of the anomaly may be a reason for dental problems; hence, it would be better to consult with a dentist and take proper remedies.

Cusp of Carabelli photos

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