Benefits of Digital Impressions in Modern Orthodontics

Benefits of Digital Impressions in Modern Orthodontics

**Early Intervention with Invisalign First for Kids**

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In the field of modern orthodontics, digital impressions have revolutionized the way dental procedures are conducted, particularly in terms of patient comfort. One of the most significant advantages of digital impressions is their non-invasive nature, which eliminates the need for uncomfortable trays filled with putty. This traditional method often leads to discomfort, anxiety, and even gagging in some patients, especially children who may have sensitive gag reflexes.


Digital impressions, on the other hand, use advanced intraoral scanners to capture precise 3D images of a patient's teeth and gums. This process is not only quick but also remarkably comfortable, allowing patients to relax during the procedure. The handheld scanners used for digital impressions are slim and less intrusive, reducing the anxiety associated with traditional methods. This improvement in patient comfort is particularly beneficial for young patients or those with sensitive gag reflexes, as it makes the dental experience much more pleasant and stress-free.


Orthodontic check-ups help track the progress of tooth movement Dental braces for children tooth.

The enhanced comfort provided by digital impressions also leads to better patient compliance and satisfaction. Patients are more cooperative during the scanning process, which in turn helps orthodontists to obtain accurate and detailed images necessary for effective treatment planning. Moreover, the precision and accuracy of digital impressions ensure that orthodontic appliances fit perfectly, reducing the need for adjustments and remakes. This streamlined process not only benefits patients but also allows orthodontists to provide more efficient and effective care, transforming the overall patient experience in modern orthodontics.

Invisalign First is designed for children aged 6 to 10, using clear, removable aligners to address early orthodontic needs, promoting proper jaw development and teeth alignment without traditional braces. —

In modern orthodontics, digital impressions have revolutionized the way treatment is structured and outcomes are optimized. One of the most significant benefits of digital impressions is their role in providing greater accuracy and precision. By using intraoral scanners, orthodontists can capture highly detailed three-dimensional models of a patient's teeth and gums. This technology allows for the precise mapping of dental contours, which is crucial for the design and fit of orthodontic appliances such as braces and clear aligners.


The accuracy provided by digital impressions is far more precise than traditional putty impressions. With traditional impressions, small flaws or bubbles in the putty could result in less accurate models, which could then prolong treatment or even cause delays. In addition, the precision offered by digital technology allows orthodontists to simulate treatment outcomes and visualize tooth movements before the treatment begins. This not only enhances the effectiveness of the treatment but also helps in streamlines the workflow, reducing the need for adjustments and remakes.


Digital impressions also enhance patient comfort and efficiency. The process is less invasive and messy, as it involves no putty or metal trays, which can trigger gagging or discomfort. Moreover, digital models can be easily stored and shareable with dental specialists, ensuring that treatment planning is optimized and communication between health care specialists is more effective. This level of precision and accuracy in digital impressions is a significant step in modern orthodontic care, ensuring that appliances fit perfectly and treatment outcomes are more effective and efficient.

**The HealthyStart System**

One of the most significant benefits of digital impressions in modern orthodontics is the reduced need for re-takes. Traditional impression methods often involve using putty-like materials that can be prone to errors, such as air bubbles or distortions, leading to inaccurate models. This can result in ill-fitting orthodontic appliances, necessitating re-takes and extending the treatment timeline. In contrast, digital impressions use advanced scanning technology to create highly accurate 3D models of a patient's teeth and gums. This precision significantly reduces the likelihood of errors, allowing orthodontists to ensure the accuracy of the impressions in real-time.


For children, in particularly, the traditional impression process can be challenging due to discomfort and anxiety. The mess and unpleasant taste of the impression material often require multiple attempts, which can be frustrating for both the child and the orthodontist. Digital impressions eliminate these issues by providing a non-invasive and comfortable experience. The use of a small handheld scanner to capture images of the teeth and gums makes the process quick and hassle-free, reducing the need for re-takes and saving valuable time.


The efficiency of digital impressions not only improves the patient experience but also enhances the workflow in orthodontic practices. By minimizing the need for re-takes, digital impressions streamline the treatment process, allowing for faster turnaround times and more effective treatment outcomes. This streamlined process is particularly beneficial for children, as it reduces anxiety and makes the overall orthodontic journey more comfortable and efficient.

**The HealthyStart System**

This non-invasive approach targets the natural development of children's teeth and jaw, using soft dental appliances to align teeth and address breathing issues, reducing the need for more invasive treatments.

In the fast-changing and technology-driven space of orthodontics, digital impressions have significantly enhanced patient care and treatment efficiency. One of the most substantial benefits of digital impressions is their ability to capture data with speed and precision. Unlike traditional impression molds, which require time to set and often result in messy and uncomfortable patient sessions, digital impressions can be taken in just a matter of minutes. This quick data capture allows orthodontists to immediately visualize and analyze the detailed 3D models of a patient's teeth, which are then shared with dental laboratories electronically.


The efficiency of digital impressions leads to faster turnaround times for treatment. Traditional dental labs often experience delays due to the need for physical impressions to be sent back and forth, which can lead to multiple sessions and longer waiting times for patients. In digital dental labs, this process is streamlined, allowing for the design and fabrication of restorations to begin immediately. This not only speeds up the treatment process but also means that patients can receive their prosthetic teeth or orthodontic appliances much faster, reducing the need for multiple clinic sessions.


Digital impressions also significantly improve patient satisfaction. The traditional method of using putty-like materials can be unpleasant and may even lead to gagging in some patients. In contrast, digital scanning is non-invasive and comfortable, providing a more positive experience for patients. Moreover, the accuracy of digital impressions helps in reducing errors and the need for redos, which can be a significant factor in patient satisfaction.


The use of digital impressions in orthodontics also allows for real-time adjustments and enhanced patient communication. Orthodontists can use these digital models to visually explain treatment plans to patients, making it easier for them to understand the proposed changes to their smiles. This improved communication and precision in treatment planning lead to more efficient and stable treatment outcomes, ensuring that patients receive the best possible care.


In short, digital impressions have been a significant step in enhancing the efficiency and patient care in orthodontics. The ability to capture data with speed and precision, combined with the comfort and accuracy they offer, make them a preferred method over traditional impressions. As technology in dentistry and orthodontics progresses, it is clear that digital impressions will be at the very foundation of future treatment planning and patient care.

**Myobrace: A No-Braces Approach**

In the field of orthodontics, digital impressions have significantly enhanced collaboration between patients and orthodontists by providing a more comprehensive and informed treatment planning process. Unlike traditional impression methods, which involve messy materials and can be time-consuming, digital impressions offer a streamlined and comfortable experience for patients. This technology uses 3D scanning to create precise virtual models of the teeth, which can be easily shared with other oral health specialists.


The ability to digitally capture every contour and detail of a patient's teeth allows orthodontists to visualize tooth movements and assess bite relationships more accurately. This not only ensures that treatment plans are tailored to individual patient's specific dental conditions but also allows for real-time adjustments to these plans. The enhanced precision and accuracy of digital impressions enable orthodontists to engage patients more fully in their treatment process. Patients can be shown detailed digital models of their teeth and proposed changes, making it easier for them to understand and agree on treatment plans.


Digital impressions also promote better collaboration between orthodontists and other dental specialists. For instance, these digital models can be shared instantly with oral surgeons or dental labs, ensuring that all team members are on the same level of treatment planning. This integration of digital technology into orthodontic care not only enhances patient education but also ensures that treatment outcomes are more precise and effective. In a digital workflow, the work of dentists and laboratory technicians is no longer separated, as they use the same digital solutions to design and manufacture dental products like aligners or appliances.


The efficiency and accuracy provided by digital impressions have transformed the way orthodontic treatment is planned and provided. Patients benefit from reduced chair time, enhanced comfort, and a more engaging treatment experience. As digital dentistry technologies become more standard, the future of orthodontic care is moving swiftly into a more streamlined, efficient, and patient-centered model.

Myobrace offers a brace-free solution that corrects poor oral habits, guiding jaw and teeth alignment development in children, promoting natural growth and oral health.

In modern orthodontics, digital impressions have revolutionized the way treatment plans are coordinated and shared among healthcare professionals. One of the significant benefits of digital impressions is their seamless integration into a comprehensive and well-informed collaboration between patients, orthodontists, and other oral health specialists. This enhanced collaboration is crucial for ensuring that treatment plans are not only effective but also tailored to meet the specific needs of each patient.


Digital impressions allow for the easy sharing of detailed 3D models of a patient's teeth and gums with specialists. This shared access enables orthodontists and other healthcare professionals to visualize and assess the patient's oral health from multiple perspectives, leading to more accurate diagnoses and treatment plans. Unlike traditional impressions, which are often physical and require physical transportation or storage, digital impressions can be instantly shared and updated, reducing the time and resources needed for communication and coordination.


Moreover, digital impressions facilitate real-time adjustments and updates to treatment plans. If a patient's needs or preferences require changes during the treatment process, these adjustments can be made quickly and accurately. This not only streamlines the treatment process but also ensures that all involved healthcare professionals are on the same page, reducing errors and improving patient outcomes.


For patients, this enhanced collaboration also leads to better engagement and education. Digital models can be used to visually explain treatment plans, making it easier for patients to understand their orthodontic journey and the expected outcomes. This transparency and involvement in the treatment process can lead to higher patient satisfaction and compliance with treatment recommendations.


Incorporating digital impressions into orthodontic care not only modernizes the field but also aligns with the overall aim of providing personalized and effective treatment. By ensuring that treatment plans are well-informed and comprehensive, digital impressions help create a more streamlined and patient-f
Incorporating digital impressions into orthodontic care not only modernizes the field but also aligns with the overall aim of providing personalized and effective treatment. By ensuring that treatment plans are well-informed and comprehensive, digital impressions help create a more streamlined and patient-f
Incorporating digital impressions into orthodontic care not only modernizes the field but also aligns with the overall aim of providing personalized and effective treatment. By ensuring that treatment plans are well-informed and comprehensive, digital impressions help create a more streamlined and patient-f
Incorporating digital impressions into orthodontic care not only modernizes the field but also aligns with the overall aim of providing personalized and effective treatment. By ensuring that treatment plans are well-informed and comprehensive, digital impressions help create a more streamlined and patient-f
Incorporating digital impressions into orthodontic care not only modernizes the field but also aligns with the overall aim of providing personalized and effective treatment. By ensuring that treatment plans are well-informed and comprehensive, digital impressions help create a more streamlined and patient-f
Incorporating digital impressions into orthodontic care not only modernizes the field but also aligns with the overall aim of providing personalized and effective treatment. By ensuring that treatment plans are well-informed and comprehensive, digital impressions help create a more streamlined and patient-f
Incorporating digital impressions into orthodontic care not only modernizes the field but also aligns with the overall aim of providing personalized and effective treatment. By ensuring that treatment plans are well-informed and comprehensive, digital impressions help create a more streamlined and patient-f
Incorporating digital impressions into orthodontic care not only modern

**Comprehensive Orthodontic Solutions**

In the modern era of orthodontics, digital impressions have not only enhanced patient comfort and treatment accuracy but also offer significant environmental benefits. One of the most significant advantages of digital impressions is their eco-friendly impact. By reducing the use of physical materials, digital impressions contribute to a more environmentally-friendly practice. Traditional impressions require the use of putty-like materials, metal trays, and films, which can generate a significant amount of waste. This waste not only requires physical storage but also can end up in landfills, contributing to environmental pollution.


Digital impressions, on the other, use intraoral scanning technology to capture a three-dimensional image of the teeth and surrounding tissues. This process eliminates the need for any physical materials, reducing waste and the environmental footprint of dental practices. The digital models can be stored electronically, making them easily shareable and storable without the need for physical space. Additionally, digital impressions can be sent electronically to dental lab, reducing the time and resources required for transportation.


The environmental benefits of digital impressions align with the global concern for sustainability. By transitioning to digital impression taking, dental professionals can actively contribute to reducing their environmental impact and support a greener future. This not only benefits the environment but also aligns with the modern dental practice's need for precision, efficiency, and patient comfort. As technology in dentistry and orthodontics further advanced, the role of digital impressions will likely play an even more crucial role in providing eco-friendly and high-quality care.

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  • Tooth decay
  • From a page move: This is a redirect from a page that has been moved (renamed). This page was kept as a redirect to avoid breaking links, both internal and external, that may have been made to the old page name.
For other uses, see Thumbsucker (disambiguation).
Infants may use pacifiers or their thumb or fingers to soothe themselves
Newborn baby thumb sucking
A bonnet macaque thumb sucking

Thumb sucking is a behavior found in humans, chimpanzees, captive ring-tailed lemurs,[1] and other primates.[2] It usually involves placing the thumb into the mouth and rhythmically repeating sucking contact for a prolonged duration. It can also be accomplished with any organ within reach (such as other fingers and toes) and is considered to be soothing and therapeutic for the person. As a child develops the habit, it will usually develop a "favourite" finger to suck on.

At birth, a baby will reflexively suck any object placed in its mouth; this is the sucking reflex responsible for breastfeeding. From the first time they engage in nutritive feeding, infants learn that the habit can not only provide valuable nourishment, but also a great deal of pleasure, comfort, and warmth. Whether from a mother, bottle, or pacifier, this behavior, over time, begins to become associated with a very strong, self-soothing, and pleasurable oral sensation. As the child grows older, and is eventually weaned off the nutritional sucking, they can either develop alternative means for receiving those same feelings of physical and emotional fulfillment, or they can continue experiencing those pleasantly soothing experiences by beginning to suck their thumbs or fingers.[3] This reflex disappears at about 4 months of age; thumb sucking is not purely an instinctive behavior and therefore can last much longer.[4] Moreover, ultrasound scans have revealed that thumb sucking can start before birth, as early as 15 weeks from conception; whether this behavior is voluntary or due to random movements of the fetus in the womb is not conclusively known.

Thumb sucking generally stops by the age of 4 years. Some older children will retain the habit, which can cause severe dental problems.[5] While most dentists would recommend breaking the habit as early as possible, it has been shown that as long as the habit is broken before the onset of permanent teeth, at around 5 years old, the damage is reversible.[6] Thumb sucking is sometimes retained into adulthood and may be due to simply habit continuation. Using anatomical and neurophysiological data a study has found that sucking the thumb is said to stimulate receptors within the brain which cause the release of mental and physical tension.[7]

Dental problems and prevention

[edit]
Alveolar prognathism, caused by thumb sucking and tongue thrusting in a 7-year-old girl.

Percentage of children who suck their thumbs (data from two researchers)

Age Kantorowicz[4] Brückl[8]
0–1 92% 66%
1–2 93%
2–3 87% –
3–4 86% 25%
4–5 85%
5–6 76%
Over 6 — 9%

Most children stop sucking on thumbs, pacifiers or other objects on their own between 2 and 4 years of age. No harm is done to their teeth or jaws until permanent teeth start to erupt. The only time it might cause concern is if it goes on beyond 6 to 8 years of age. At this time, it may affect the shape of the oral cavity or dentition.[9] During thumbsucking the tongue sits in a lowered position and so no longer balances the forces from the buccal group of musculature. This results in narrowing of the upper arch and a posterior crossbite. Thumbsucking can also cause the maxillary central incisors to tip labially and the mandibular incisors to tip lingually, resulting in an increased overjet and anterior open bite malocclusion, as the thumb rests on them during the course of sucking. In addition to proclination of the maxillary incisors, mandibular incisors retrusion will also happen. Transverse maxillary deficiency gives rise to posterior crossbite, ultimately leading to a Class II malocclusion.[10]

Children may experience difficulty in swallowing and speech patterns due to the adverse changes. Aside from the damaging physical aspects of thumb sucking, there are also additional risks, which unfortunately, are present at all ages. These include increased risk of infection from communicable diseases, due to the simple fact that non-sterile thumbs are covered with infectious agents, as well as many social implications. Some children experience social difficulties, as often children are taunted by their peers for engaging in what they can consider to be an “immature” habit. This taunting often results the child being rejected by the group or being subjected to ridicule by their peers, which can cause understandable psychological stress.[11]

Methods to stop sucking habits are divided into 2 categories: Preventive Therapy and Appliance Therapy.[10]

Examples to prevent their children from sucking their thumbs include the use of bitterants or piquant substances on their child's hands—although this is not a procedure encouraged by the American Dental Association[9] or the Association of Pediatric Dentists. Some suggest that positive reinforcements or calendar rewards be given to encourage the child to stop sucking their thumb.

The American Dental Association recommends:

  • Praise children for not sucking, instead of scolding them when they do.
  • If a child is sucking their thumb when feeling insecure or needing comfort, focus instead on correcting the cause of the anxiety and provide comfort to your child.
  • If a child is sucking on their thumb because of boredom, try getting the child's attention with a fun activity.
  • Involve older children in the selection of a means to cease thumb sucking.
  • The pediatric dentist can offer encouragement to the child and explain what could happen to the child's teeth if he/she does not stop sucking.
  • Only if these tips are ineffective, remind the child of the habit by bandaging the thumb or putting a sock/glove on the hand at night.
  • Other orthodontics[12] for appliances are available.

The British Orthodontic Society recommends the same advice as ADA.[13]

A Cochrane review was conducted to review the effectiveness of a variety of clinical interventions for stopping thumb-sucking. The study showed that orthodontic appliances and psychological interventions (positive and negative reinforcement) were successful at preventing thumb sucking in both the short and long term, compared to no treatment.[14] Psychological interventions such as habit reversal training and decoupling have also proven useful in body focused repetitive behaviors.[15]

Clinical studies have shown that appliances such as TGuards can be 90% effective in breaking the thumb or finger sucking habit. Rather than use bitterants or piquants, which are not endorsed by the ADA due to their causing of discomfort or pain, TGuards break the habit simply by removing the suction responsible for generating the feelings of comfort and nurture.[16] Other appliances are available, such as fabric thumb guards, each having their own benefits and features depending on the child's age, willpower and motivation. Fixed intraoral appliances have been known to create problems during eating as children when removing their appliances may have a risk of breaking them. Children with mental illness may have reduced compliance.[10]

Some studies mention the use of extra-oral habit reminder appliance to treat thumb sucking. An alarm is triggered when the child tries to suck the thumb to stop the child from this habit.[10][17] However, more studies are required to prove the effectiveness of external devices on thumb sucking.

Children's books

[edit]
  • In Heinrich Hoffmann’s Struwwelpeter, the "thumb-sucker" Konrad is punished by having both of his thumbs cut off.
  • There are several children's books on the market with the intention to help the child break the habit of thumb sucking. Most of them provide a story the child can relate to and some coping strategies.[18] Experts recommend to use only books in which the topic of thumb sucking is shown in a positive and respectful way.[19]

See also

[edit]
  • Stereotypic movement disorder
  • Prognathism

References

[edit]
  1. ^ Jolly A (1966). Lemur Behavior. Chicago: University of Chicago Press. p. 65. ISBN 978-0-226-40552-0.
  2. ^ Benjamin, Lorna S.: "The Beginning of Thumbsucking." Child Development, Vol. 38, No. 4 (Dec., 1967), pp. 1065–1078.
  3. ^ "About the Thumb Sucking Habit". Tguard.
  4. ^ a b Kantorowicz A (June 1955). "Die Bedeutung des Lutschens für die Entstehung erworbener Fehlbildungen". Fortschritte der Kieferorthopädie. 16 (2): 109–21. doi:10.1007/BF02165710. S2CID 28204791.
  5. ^ O'Connor A (27 September 2005). "The Claim: Thumb Sucking Can Lead to Buck Teeth". The New York Times. Retrieved 1 August 2012.
  6. ^ Friman PC, McPherson KM, Warzak WJ, Evans J (April 1993). "Influence of thumb sucking on peer social acceptance in first-grade children". Pediatrics. 91 (4): 784–6. doi:10.1542/peds.91.4.784. PMID 8464667.
  7. ^ Ferrante A, Ferrante A (August 2015). "[Finger or thumb sucking. New interpretations and therapeutic implications]". Minerva Pediatrica (in Italian). 67 (4): 285–97. PMID 26129804.
  8. ^ Reichenbach E, Brückl H (1982). "Lehrbuch der Kieferorthopädie Bd. 1962;3:315-26.". Kieferorthopädische Klinik und Therapie Zahnärzliche Fortbildung. 5. Auflage Verlag. JA Barth Leipzig" alıntı Schulze G.
  9. ^ a b "Thumbsucking - American Dental Association". Archived from the original on 2010-06-19. Retrieved 2010-05-19.
  10. ^ a b c d Shetty RM, Shetty M, Shetty NS, Deoghare A (2015). "Three-Alarm System: Revisited to treat Thumb-sucking Habit". International Journal of Clinical Pediatric Dentistry. 8 (1): 82–6. doi:10.5005/jp-journals-10005-1289. PMC 4472878. PMID 26124588.
  11. ^ Fukuta O, Braham RL, Yokoi K, Kurosu K (1996). "Damage to the primary dentition resulting from thumb and finger (digit) sucking". ASDC Journal of Dentistry for Children. 63 (6): 403–7. PMID 9017172.
  12. ^ "Stop Thumb Sucking". Stop Thumb Sucking.org.
  13. ^ "Dummy and thumb sucking habits" (PDF). Patient Information Leaflet. British Orthodontic Society.
  14. ^ Borrie FR, Bearn DR, Innes NP, Iheozor-Ejiofor Z (March 2015). "Interventions for the cessation of non-nutritive sucking habits in children". The Cochrane Database of Systematic Reviews. 2021 (3): CD008694. doi:10.1002/14651858.CD008694.pub2. PMC 8482062. PMID 25825863.
  15. ^ Lee MT, Mpavaenda DN, Fineberg NA (2019-04-24). "Habit Reversal Therapy in Obsessive Compulsive Related Disorders: A Systematic Review of the Evidence and CONSORT Evaluation of Randomized Controlled Trials". Frontiers in Behavioral Neuroscience. 13: 79. doi:10.3389/fnbeh.2019.00079. PMC 6491945. PMID 31105537.
  16. ^ "Unique Thumb with Lock Band to Deter Child from Thumb Sucking". Clinical Research Associates Newsletter. 19 (6). June 1995.
  17. ^ Krishnappa S, Rani MS, Aariz S (2016). "New electronic habit reminder for the management of thumb-sucking habit". Journal of Indian Society of Pedodontics and Preventive Dentistry. 34 (3): 294–7. doi:10.4103/0970-4388.186750. PMID 27461817. S2CID 22658574.
  18. ^ "Books on the Subject of Thumb-Sucking". Thumb-Heroes. 9 December 2020.
  19. ^ Stevens Mills, Christine (2018). Two Thumbs Up - Understanding and Treatment of Thumb Sucking. ISBN 978-1-5489-2425-6.

Further reading

[edit]
  • "Duration of pacifier use, thumb sucking may affect dental arches". The Journal of the American Dental Association. 133 (12): 1610–1612. December 2002. doi:10.14219/jada.archive.2002.0102.
  • Mobbs E, Crarf GT (2011). Latchment Before Attachment, The First Stage of Emotional Development, Oral Tactile Imprinting. Westmead.
[edit]
  • "Oral Health Topics: Thumbsucking". American Dental Association. Archived from the original on 2010-06-19.
  • "Pacifiers & Thumb Sucking". Canadian Dental Association.
This article is about teeth in general. For specifically human teeth, see Human tooth. For other uses, see Tooth (disambiguation).

 

Tooth
A chimpanzee displaying his teeth
Details
Identifiers
Latin dens
MeSH D014070
FMA 12516
Anatomical terminology
[edit on Wikidata]

A tooth (pl.: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tearing food, for defensive purposes, to intimidate other animals often including their own, or to carry prey or their young. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of multiple tissues of varying density and hardness that originate from the outermost embryonic germ layer, the ectoderm.

The general structure of teeth is similar across the vertebrates, although there is considerable variation in their form and position. The teeth of mammals have deep roots, and this pattern is also found in some fish, and in crocodilians. In most teleost fish, however, the teeth are attached to the outer surface of the bone, while in lizards they are attached to the inner surface of the jaw by one side. In cartilaginous fish, such as sharks, the teeth are attached by tough ligaments to the hoops of cartilage that form the jaw.[1]

Monophyodonts are animals that develop only one set of teeth, while diphyodonts grow an early set of deciduous teeth and a later set of permanent or "adult" teeth. Polyphyodonts grow many sets of teeth. For example, sharks, grow a new set of teeth every two weeks to replace worn teeth. Most extant mammals including humans are diphyodonts, but there are exceptions including elephants, kangaroos, and manatees, all of which are polyphyodonts.

Rodent incisors grow and wear away continually through gnawing, which helps maintain relatively constant length. The industry of the beaver is due in part to this qualification. Some rodents, such as voles and guinea pigs (but not mice), as well as lagomorpha (rabbits, hares and pikas), have continuously growing molars in addition to incisors.[2][3] Also, tusks (in tusked mammals) grow almost throughout life.[4]

Teeth are not always attached to the jaw, as they are in mammals. In many reptiles and fish, teeth are attached to the palate or to the floor of the mouth, forming additional rows inside those on the jaws proper. Some teleosts even have teeth in the pharynx. While not true teeth in the usual sense, the dermal denticles of sharks are almost identical in structure and are likely to have the same evolutionary origin. Indeed, teeth appear to have first evolved in sharks, and are not found in the more primitive jawless fish – while lampreys do have tooth-like structures on the tongue, these are in fact, composed of keratin, not of dentine or enamel, and bear no relationship to true teeth.[1] Though "modern" teeth-like structures with dentine and enamel have been found in late conodonts, they are now supposed to have evolved independently of later vertebrates' teeth.[5][6]

Living amphibians typically have small teeth, or none at all, since they commonly feed only on soft foods. In reptiles, teeth are generally simple and conical in shape, although there is some variation between species, most notably the venom-injecting fangs of snakes. The pattern of incisors, canines, premolars and molars is found only in mammals, and to varying extents, in their evolutionary ancestors. The numbers of these types of teeth vary greatly between species; zoologists use a standardised dental formula to describe the precise pattern in any given group.[1]

Etymology

[edit]

The word tooth comes from Proto-Germanic *tanþs, derived from the Proto-Indo-European *h₁dent-, which was composed of the root *h₁ed- 'to eat' plus the active participle suffix *-nt, therefore literally meaning 'that which eats'.[7]

The irregular plural form teeth is the result of Germanic umlaut whereby vowels immediately preceding a high vocalic in the following syllable were raised. As the nominative plural ending of the Proto-Germanic consonant stems (to which *tanþs belonged) was *-iz, the root vowel in the plural form *tanþiz (changed by this point to *tÄ…Ì„þi via unrelated phonological processes) was raised to /œÃ‹Â/, and later unrounded to /eː/, resulting in the tōþ/tÄ“þ alternation attested from Old English. Cf. also Old English bōc/bÄ“Ä‹ 'book/books' and 'mÅ«s/mȳs' 'mouse/mice', from Proto-Germanic *bōks/bōkiz and *mÅ«s/mÅ«siz respectively.

Cognate with Latin dÄ“ns, Greek á½€δούς (odous), and Sanskrit dát.

Origin

[edit]

Teeth are assumed to have evolved either from ectoderm denticles (scales, much like those on the skin of sharks) that folded and integrated into the mouth (called the "outside–in" theory), or from endoderm pharyngeal teeth (primarily formed in the pharynx of jawless vertebrates) (the "inside–out" theory). In addition, there is another theory stating that neural crest gene regulatory network, and neural crest-derived ectomesenchyme are the key to generate teeth (with any epithelium, either ectoderm or endoderm).[4][8]

The genes governing tooth development in mammals are homologous to those involved in the development of fish scales.[9] Study of a tooth plate of a fossil of the extinct fish Romundina stellina showed that the teeth and scales were made of the same tissues, also found in mammal teeth, lending support to the theory that teeth evolved as a modification of scales.[10]

Mammals

[edit]
Main article: Mammal tooth

Teeth are among the most distinctive (and long-lasting) features of mammal species. Paleontologists use teeth to identify fossil species and determine their relationships. The shape of the animal's teeth are related to its diet. For example, plant matter is hard to digest, so herbivores have many molars for chewing and grinding. Carnivores, on the other hand, have canine teeth to kill prey and to tear meat.

Mammals, in general, are diphyodont, meaning that they develop two sets of teeth. In humans, the first set (the "baby", "milk", "primary" or "deciduous" set) normally starts to appear at about six months of age, although some babies are born with one or more visible teeth, known as neonatal teeth. Normal tooth eruption at about six months is known as teething and can be painful. Kangaroos, elephants, and manatees are unusual among mammals because they are polyphyodonts.

Aardvark

[edit]

In aardvarks, teeth lack enamel and have many pulp tubules, hence the name of the order Tubulidentata.[11]

Canines

[edit]

In dogs, the teeth are less likely than humans to form dental cavities because of the very high pH of dog saliva, which prevents enamel from demineralizing.[12] Sometimes called cuspids, these teeth are shaped like points (cusps) and are used for tearing and grasping food.[13]

Cetaceans

[edit]
Main article: Baleen

Like human teeth, whale teeth have polyp-like protrusions located on the root surface of the tooth. These polyps are made of cementum in both species, but in human teeth, the protrusions are located on the outside of the root, while in whales the nodule is located on the inside of the pulp chamber. While the roots of human teeth are made of cementum on the outer surface, whales have cementum on the entire surface of the tooth with a very small layer of enamel at the tip. This small enamel layer is only seen in older whales where the cementum has been worn away to show the underlying enamel.[14]

The toothed whale is a parvorder of the cetaceans characterized by having teeth. The teeth differ considerably among the species. They may be numerous, with some dolphins bearing over 100 teeth in their jaws. On the other hand, the narwhals have a giant unicorn-like tusk, which is a tooth containing millions of sensory pathways and used for sensing during feeding, navigation, and mating. It is the most neurologically complex tooth known. Beaked whales are almost toothless, with only bizarre teeth found in males. These teeth may be used for feeding but also for demonstrating aggression and showmanship.

Primates

[edit]
Main articles: Human tooth and Dental anatomy

In humans (and most other primates), there are usually 20 primary (also "baby" or "milk") teeth, and later up to 32 permanent teeth. Four of these 32 may be third molars or wisdom teeth, although these are not present in all adults, and may be removed surgically later in life.[15]

Among primary teeth, 10 of them are usually found in the maxilla (i.e. upper jaw) and the other 10 in the mandible (i.e. lower jaw). Among permanent teeth, 16 are found in the maxilla and the other 16 in the mandible. Most of the teeth have uniquely distinguishing features.

Horse

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Main article: Horse teeth

An adult horse has between 36 and 44 teeth. The enamel and dentin layers of horse teeth are intertwined.[16] All horses have 12 premolars, 12 molars, and 12 incisors.[17] Generally, all male equines also have four canine teeth (called tushes) between the molars and incisors. However, few female horses (less than 28%) have canines, and those that do usually have only one or two, which many times are only partially erupted.[18] A few horses have one to four wolf teeth, which are vestigial premolars, with most of those having only one or two. They are equally common in male and female horses and much more likely to be on the upper jaw. If present these can cause problems as they can interfere with the horse's bit contact. Therefore, wolf teeth are commonly removed.[17]

Horse teeth can be used to estimate the animal's age. Between birth and five years, age can be closely estimated by observing the eruption pattern on milk teeth and then permanent teeth. By age five, all permanent teeth have usually erupted. The horse is then said to have a "full" mouth. After the age of five, age can only be conjectured by studying the wear patterns on the incisors, shape, the angle at which the incisors meet, and other factors. The wear of teeth may also be affected by diet, natural abnormalities, and cribbing. Two horses of the same age may have different wear patterns.

A horse's incisors, premolars, and molars, once fully developed, continue to erupt as the grinding surface is worn down through chewing. A young adult horse will have teeth, which are 110–130 mm (4.5–5 inches) long, with the majority of the crown remaining below the gumline in the dental socket. The rest of the tooth will slowly emerge from the jaw, erupting about 3 mm (1⁄8 in) each year, as the horse ages. When the animal reaches old age, the crowns of the teeth are very short and the teeth are often lost altogether. Very old horses, if lacking molars, may need to have their fodder ground up and soaked in water to create a soft mush for them to eat in order to obtain adequate nutrition.

Proboscideans

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Section through the ivory tusk of a mammoth
Main article: Elephant ivory

Elephants' tusks are specialized incisors for digging food up and fighting. Some elephant teeth are similar to those in manatees, and elephants are believed to have undergone an aquatic phase in their evolution.

At birth, elephants have a total of 28 molar plate-like grinding teeth not including the tusks. These are organized into four sets of seven successively larger teeth which the elephant will slowly wear through during its lifetime of chewing rough plant material. Only four teeth are used for chewing at a given time, and as each tooth wears out, another tooth moves forward to take its place in a process similar to a conveyor belt. The last and largest of these teeth usually becomes exposed when the animal is around 40 years of age, and will often last for an additional 20 years. When the last of these teeth has fallen out, regardless of the elephant's age, the animal will no longer be able to chew food and will die of starvation.[19][20]

Rabbit

[edit]

Rabbits and other lagomorphs usually shed their deciduous teeth before (or very shortly after) their birth, and are usually born with their permanent teeth.[21] The teeth of rabbits complement their diet, which consists of a wide range of vegetation. Since many of the foods are abrasive enough to cause attrition, rabbit teeth grow continuously throughout life.[22] Rabbits have a total of six incisors, three upper premolars, three upper molars, two lower premolars, and two lower molars on each side. There are no canines. Dental formula is 2.0.3.31.0.2.3 = 28. Three to four millimeters of the tooth is worn away by incisors every week, whereas the cheek teeth require a month to wear away the same amount.[23]

The incisors and cheek teeth of rabbits are called aradicular hypsodont teeth. This is sometimes referred to as an elodent dentition. These teeth grow or erupt continuously. The growth or eruption is held in balance by dental abrasion from chewing a diet high in fiber.

Buccal view of top incisor from Rattus rattus. Top incisor outlined in yellow. Molars circled in blue.
Buccal view of the lower incisor from the right dentary of a Rattus rattus
Lingual view of the lower incisor from the right dentary of a Rattus rattus
Midsagittal view of top incisor from Rattus rattus. Top incisor outlined in yellow. Molars circled in blue.

Rodents

[edit]

Rodents have upper and lower hypselodont incisors that can continuously grow enamel throughout its life without having properly formed roots.[24] These teeth are also known as aradicular teeth, and unlike humans whose ameloblasts die after tooth development, rodents continually produce enamel, they must wear down their teeth by gnawing on various materials.[25] Enamel and dentin are produced by the enamel organ, and growth is dependent on the presence of stem cells, cellular amplification, and cellular maturation structures in the odontogenic region.[26] Rodent incisors are used for cutting wood, biting through the skin of fruit, or for defense. This allows for the rate of wear and tooth growth to be at equilibrium.[24] The microstructure of rodent incisor enamel has shown to be useful in studying the phylogeny and systematics of rodents because of its independent evolution from the other dental traits. The enamel on rodent incisors are composed of two layers: the inner portio interna (PI) with Hunter-Schreger bands (HSB) and an outer portio externa (PE) with radial enamel (RE).[27] It usually involves the differential regulation of the epithelial stem cell niche in the tooth of two rodent species, such as guinea pigs.[28][29]

Lingual view of top incisor from Rattus rattus. Top incisor outlined in yellow. Molars circled in blue.

The teeth have enamel on the outside and exposed dentin on the inside, so they self-sharpen during gnawing. On the other hand, continually growing molars are found in some rodent species, such as the sibling vole and the guinea pig.[28][29] There is variation in the dentition of the rodents, but generally, rodents lack canines and premolars, and have a space between their incisors and molars, called the diastema region.

Manatee

[edit]

Manatees are polyphyodont with mandibular molars developing separately from the jaw and are encased in a bony shell separated by soft tissue.[30][31]

Walrus

[edit]
Main article: Walrus ivory

Walrus tusks are canine teeth that grow continuously throughout life.[32]

Fish

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Teeth of a great white shark
See also: Pharyngeal teeth and Shark tooth

Fish, such as sharks, may go through many teeth in their lifetime. The replacement of multiple teeth is known as polyphyodontia.

A class of prehistoric shark are called cladodonts for their strange forked teeth.

Unlike the continuous shedding of functional teeth seen in modern sharks,[33][34] the majority of stem chondrichthyan lineages retained all tooth generations developed throughout the life of the animal.[35] This replacement mechanism is exemplified by the tooth whorl-based dentitions of acanthodians,[36] which include the oldest known toothed vertebrate, Qianodus duplicis[37].

Amphibians

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All amphibians have pedicellate teeth, which are modified to be flexible due to connective tissue and uncalcified dentine that separates the crown from the base of the tooth.[38]

Most amphibians exhibit teeth that have a slight attachment to the jaw or acrodont teeth. Acrodont teeth exhibit limited connection to the dentary and have little enervation.[39] This is ideal for organisms who mostly use their teeth for grasping, but not for crushing and allows for rapid regeneration of teeth at a low energy cost. Teeth are usually lost in the course of feeding if the prey is struggling. Additionally, amphibians that undergo a metamorphosis develop bicuspid shaped teeth.[40]

Reptiles

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The teeth of reptiles are replaced constantly throughout their lives. Crocodilian juveniles replace teeth with larger ones at a rate as high as one new tooth per socket every month. Once mature, tooth replacement rates can slow to two years and even longer. Overall, crocodilians may use 3,000 teeth from birth to death. New teeth are created within old teeth.[41]

Birds

[edit]
Main article: Ichthyornis

A skull of Ichthyornis discovered in 2014 suggests that the beak of birds may have evolved from teeth to allow chicks to escape their shells earlier, and thus avoid predators and also to penetrate protective covers such as hard earth to access underlying food.[42][43]

Invertebrates

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The European medicinal leech has three jaws with numerous sharp teeth which function like little saws for incising a host.

True teeth are unique to vertebrates,[44] although many invertebrates have analogous structures often referred to as teeth. The organisms with the simplest genome bearing such tooth-like structures are perhaps the parasitic worms of the family Ancylostomatidae.[45] For example, the hookworm Necator americanus has two dorsal and two ventral cutting plates or teeth around the anterior margin of the buccal capsule. It also has a pair of subdorsal and a pair of subventral teeth located close to the rear.[46]

Historically, the European medicinal leech, another invertebrate parasite, has been used in medicine to remove blood from patients.[47] They have three jaws (tripartite) that resemble saws in both appearance and function, and on them are about 100 sharp teeth used to incise the host. The incision leaves a mark that is an inverted Y inside of a circle. After piercing the skin and injecting anticoagulants (hirudin) and anaesthetics, they suck out blood, consuming up to ten times their body weight in a single meal.[48]

In some species of Bryozoa, the first part of the stomach forms a muscular gizzard lined with chitinous teeth that crush armoured prey such as diatoms. Wave-like peristaltic contractions then move the food through the stomach for digestion.[49]

The limpet rasps algae from rocks using teeth with the strongest known tensile strength of any biological material.

Molluscs have a structure called a radula, which bears a ribbon of chitinous teeth. However, these teeth are histologically and developmentally different from vertebrate teeth and are unlikely to be homologous. For example, vertebrate teeth develop from a neural crest mesenchyme-derived dental papilla, and the neural crest is specific to vertebrates, as are tissues such as enamel.[44]

The radula is used by molluscs for feeding and is sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, typically used for scraping or cutting food before the food enters the oesophagus. The radula is unique to molluscs, and is found in every class of mollusc apart from bivalves.

Within the gastropods, the radula is used in feeding by both herbivorous and carnivorous snails and slugs. The arrangement of teeth (also known as denticles) on the radula ribbon varies considerably from one group to another as shown in the diagram on the left.

Predatory marine snails such as the Naticidae use the radula plus an acidic secretion to bore through the shell of other molluscs. Other predatory marine snails, such as the Conidae, use a specialized radula tooth as a poisoned harpoon. Predatory pulmonate land slugs, such as the ghost slug, use elongated razor-sharp teeth on the radula to seize and devour earthworms. Predatory cephalopods, such as squid, use the radula for cutting prey.

In most of the more ancient lineages of gastropods, the radula is used to graze by scraping diatoms and other microscopic algae off rock surfaces and other substrates. Limpets scrape algae from rocks using radula equipped with exceptionally hard rasping teeth.[50] These teeth have the strongest known tensile strength of any biological material, outperforming spider silk.[50] The mineral protein of the limpet teeth can withstand a tensile stress of 4.9 GPa, compared to 4 GPa of spider silk and 0.5 GPa of human teeth.[51]

 

Fossilization and taphonomy

[edit]

Because teeth are very resistant, often preserved when bones are not,[52] and reflect the diet of the host organism, they are very valuable to archaeologists and palaeontologists.[53] Early fish such as the thelodonts had scales composed of dentine and an enamel-like compound, suggesting that the origin of teeth was from scales which were retained in the mouth. Fish as early as the late Cambrian had dentine in their exoskeletons, which may have functioned in defense or for sensing their environments.[54] Dentine can be as hard as the rest of teeth and is composed of collagen fibres, reinforced with hydroxyapatite.[54]

Though teeth are very resistant, they also can be brittle and highly susceptible to cracking.[55] However, cracking of the tooth can be used as a diagnostic tool for predicting bite force. Additionally, enamel fractures can also give valuable insight into the diet and behaviour of archaeological and fossil samples.

Decalcification removes the enamel from teeth and leaves only the organic interior intact, which comprises dentine and cementine.[56] Enamel is quickly decalcified in acids,[57] perhaps by dissolution by plant acids or via diagenetic solutions, or in the stomachs of vertebrate predators.[56] Enamel can be lost by abrasion or spalling,[56] and is lost before dentine or bone are destroyed by the fossilisation process.[57] In such a case, the 'skeleton' of the teeth would consist of the dentine, with a hollow pulp cavity.[56] The organic part of dentine, conversely, is destroyed by alkalis.[57]

See also

[edit]
  • Animal tooth development
  • Dragon's teeth (mythology)

References

[edit]
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Sources

[edit]
  • Shoshani, Jeheskel (2002). "Tubulidentata". In Robertson, Sarah (ed.). Encyclopedia of Life Sciences. Vol. 18: Svedberg, Theodor to Two-hybrid and Related Systems. London, UK: Nature Publishing Group. ISBN 978-1-56159-274-6.
[edit]
Wikimedia Commons has media related to tooth.
 
Look up tooth in Wiktionary, the free dictionary.
  • Beach, Chandler B., ed. (1914). "Teeth" . The New Student's Reference Work . Chicago: F. E. Compton and Co.

 

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