mandibular buccal exostosis

  • Home
  • Q & A
  • Blog
  • Contact
gum exostosis? Care to share your International Journal of Dentistry and Oral Health Mandibular Tori Causes. M27.8 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Tori, Torus, Exostoses It is also possible to have a bony growth that doesn’t belong there. This results in lesions which are thick, white and velvety on the inside of the cheeks within the mouth. The patient also stated that he had difficulty in placing and removing his RPD, and had trouble with food impaction below the buccal exostosis. Torus mandibularis. Applicable To. Torus: A slow-growing bump of excess bone found in the mouth. One of the most common oral surgical procedures we perform is removal of mandibular and maxillary torus and exostosis. White sponge nevus WSN, is an autosomal dominant condition of the oral mucosa (the mucous membrane lining of the mouth). Buccal exostoses are broad-based, non-malignant surface growth occurring on the outer or facial surface of the maxilla and/or mandible, found usually in the premolar and molar region. Bilateral removal of maxillary posterior exostosis as well as removal of upper left posterior dentition prior to fabrication of a denture. ulceration in oral mucosa. Their etiology remains unknown, though The surgery July 2013;Vol. Place maxillary premolars and molars with their long axes at right angles to the occlusal plane. Torus palatinus is a common developmental exostosis or outgrowth of the bone of the hard palate that manifests itself in adults at about the age of 30. Finally, if it occurs inside the mouth, it is more specifically a buccal exostosis. 2. Buccal exostoses (“buttressing bone”) appear as a bilateral row of smooth bony nodules along the facial alveolar process of the mandible and/or maxilla. Buccal exostosis – this type is painless; Retrocalcaneal exostosis – this is a painful bump and you may also have tenderness, swelling, or redness along the bony prominence on the back side of your heel. Exostoses are nodular lumps of mature maxilla and mandible, and when located in the palate or lingual aspect of the mandible, they are called tori. Arrangement of 20 Degree Posterior Teeth: Place the maxillary 1st & 2nd PM with its long axis at right angles to the occlusal plane. The size Exostosis or hyperostoses are localized cortical bone growth on the mandible and maxilla. In any of these locations, tori manifest themselves as a hard, smooth lump of bone or cartilage covered by a relatively thin layer of soft tissue. Bony growth in the mandible along the surface nearest to the tongue. 21. Footnote: Lateral radiograph of ankles showing bony enlargement at the posterosuperior aspect of both calcaneum [Source 61)] Buccal exostosis. Oral mucosa can be divided into three main categories based on function and histology: . Left and right sides. Buccal exostoses are hard bony protrusions on the outside of your gums and are less common. Torus palatinus is often a singular growth, whereas torus mandibularus and buccal exostoses tend to be bilateral, meaning they happen on both sides of the mouth. Exostoses and tori. They begin to develop in early adulthood and may very slowly enlarge over years. More commonly seen in the maxilla than the mandible, buccal exostoses are considered to be site specific. Mandibular Tori which are present on lingual aspect of mandibular bicuspid and are usually bilateral. ent of implants in the future. Etiology is still not established, but it has been suggested that the bony overgrowth can be because of abnormally increased masticatory forces to the teeth. It is commonly seen in maxilla than mandible, whereas the etiology remains unclear. Exostoses are protuberances of bone that arise from the cortical plates in the maxilla and mandible.Buccal exostoses occur as bilateral, smooth bony masses along the buccal aspect of the maxillary and/or mandibular alveolar ridge, usually in the premolar-molar area. Development is influenced by four main risk factors. Buccal exostoses are multiple and often bilateral benign bone protuberances arising from the maxilla and/or the mandibula. The buccal and lingual cusps are placed on the plane. I do not, however, have a Type A personality, although I do sometimes grind my teeth. Medical conditions similar to or like. While buccal exostoses affect the vestibular side of the alveolar process in the maxilla and/or the mandible, usually in the molar and premolar region, palatal exostoses are found on the surface of the posterior alveolar process, usually in the area of the maxillary tuberosity [2 2 Jainkittivong A, Langlais RP. Exostoses • Typically buccal posterior • May occur anywhere on alveolus • Adult onset • Bone hard • May interfere with prostheses. Comment Buccal exostoses are multiple and often bilateral benign bone protuberances arising from the maxilla and/or the mandibula. Buccal Exostosis and Excessive Undercuts. This contributes to periodontal disease of adjoining teeth if the patient's oral hygiene is poor. They are benign, broad-based surface masses on the outer or facial aspect of the jaw bones; slowly enlarge over the years to form the bulky masses. Buccal exostosis is benign, broad-based surface masses of the outer or facial aspect of the maxilla and less commonly, the mandible. Buccal exostoses are benign, broad-based surface masses of the outer or facial aspect of the maxilla and less commonly, the mandible. With the higher availability of both 3D imaging and printing, 3D surgical guides have been used more frequently in orthodontics. Massive buccal and lingual tori. Exostosis on the buccal surface (cheek side) of the alveolar ridge of the maxilla or mandible. Buccal exostosis are rare, hard bony growth found on the maxillary alveolus.They are self-limiting and painless. Tori may form on the roof of your mouth (palatal tori), alongside your bottom row of molars (mandibular tori), or on the cheek-facing gums of the upper molars (buccal exostoses). The 2022 edition of ICD-10-CM M27.8 became effective on October 1, 2021. After obtaining appropriate anesthesia bilaterally from the maxillary tuberosities to the maxillary canines, and An unusual case of multiple mandibular buccal exostosis reported to our periodontal office with a chief complaint of unaesthetic appearance. Buccal exostoses are broad-based, non-malignant surface growth occurring on the outer or facial surface of the maxilla and/or mandible, found usually in the premolar and molar region. It is more common in women and is always located in the midline. Referred to as tori when there are multiple growths, they are normally harmless. The patient had no mandibular exostosis, nor mandibular or palatine tori. 20 Eskimo mandible #2. Their etiology remains unknown, though several factors might contribute to their development, such as genetic factors, increased masticatory function, or eating habits. Torus y Exostosis • Protuberancias óseas de crecimiento lento y limitado. A buccal exostosis is an exostosis (bone prominence) on the buccal surface (cheek side) of the alveolar ridge of the maxilla or mandible. It is caused by a mutations in certain genes coding for keratin, which causes a defect in the normal process of keratinization of the mucosa. 1. Exostosis of the mouth or jaw is called buccal exostosis A buccal exostosis is an exostosis (bone prominence) on the buccal surface (cheek side) of the alveolar ridge of the maxilla or mandible.More commonly seen in the maxilla than the mandible, buccal exostoses are considered to be site specific. More commonly seen in the maxilla than the mandible, buccal exostoses are considered to be site specific. Also, unilateral mandibular condyle malfunction can result in over-compensation of the affected muscle and tendon origins and insertions, resulting in facial asymmetry (Keenleyside, 2003). Gross removal of extra bone using Piezo osteotomy tips. It is also possible for the area to heal poorly. Basha S, Dutt SC. (AAP) Applicable Codes . Heel of the foot or Haglund's deformity. It can occur in any bone and be triggered by a number of factors. More commonly seen in the maxilla than the mandible, buccal exostoses are considered to be site specific. Cancers called osteomas and sarcomas can form cause unusual bone growth in the mouth. Buccal exostoses are broad-based, non-malignant surface growth occurring on the outer or facial surface of the maxilla and/or mandible, found usually in the premolar and molar region. Can buccal exostosis cause pain? 69 Another view of tori and crowns. The palatal torus is found only in the midline of the hard palate. As explained earlier, mandibular tori or torus mandibularis is a bony structure found on the inside of the lower jaw and the tongue. The surgery July 2013;Vol. The pain usually becomes worse when wearing shoes that rub the back of … Basha S, Dutt SC. Exostosis can affect any bone, including the knee and heel of the foot. No additional exam was necessary, thus proceed exostosis excision and bone regularization with hand piece under continue irrigation with physiology solution 0.9% in ambulatory (Figure 2A-2C). Abstract. They are less common on the lower jaw. The buccal exostosis is found only on the facial surface of the alveolar bone, usually the maxillary alveolus. Lining mucosa, nonkeratinized stratified squamous epithelium, found almost everywhere else in the oral cavity, including the: . Around 80% to 90% of these lesions present bilaterally near the bicuspid and tricuspid teeth and superior to the mylohyoid muscle, a paired muscle for mandibular attachment. It is more common in women and is always located in the midline. The procedure can be done quite atraumatically with rapid recovery using minimally-invasive techniques: Gentle reflection of the gum tissue. Fine removal and re-shaping of bone using Piezo sculpting tips. It can occur in many parts of the body. For this reason the A local anesthetic should ‘ .nfiltrated around the area i~trasptal alveoplasty s~?uld reduce the thickness of the requiring bony Tprlion. Oral maxillary exostoses are proliferating bone lesions with an unknown etiology occurring on the cortical plates both in the maxilla and in the mandible of young individuals, showing a typical slow but continuous enlargement. Exostoses are defined as benign growths of bone extending outwards from the surface of a bone. The following list(s) of procedure and/or diagnosis codes is provided for reference purposes only and may not be all inclusive. It is therefore possible that the individual PRII3 had an asymmetric face, with a larger right buccal side and chronic mandibular hypomobility. Buccal exostosis resection is performed with a local anesthetic. They begin to develop in early adulthood and may very slowly enlarge over the years. The 2022 edition of ICD-10-CM M27.8 became effective on October 1, 2021. 3. The ICD-10-CM code M27.8 might also be used to specify conditions or terms like abnormal jaw movement, abnormal jaw opening, buccal exostosis, cherubic facies, cherubism with gingival fibromatosis , condylar hyperplasia with mandibular asymmetry, etc. The prognosis for a positive end result following buccal exostosis resection is good. 2. more common in the maxilla than the mandible. 23 Mandibular tori. Among the different types of exostoses on jaws the palatal one is more common than other types. They tend to appear in early adolescence … A 55-year-old female reported with the complaint of swelling in the lower anterior region. (1) Background: Miniscrew insertion, using a surgical guide, aims to avoid possible adverse effects or complications. In principle, they’re the same as bone spurs, except that because they’re rounded and smooth, they are largely painless and pose no harm. Bony surface proliferations found in another site are typically given the generic diagnosis of … Exostoses are multiple small bony nodules occurring along the buccal or palatal aspects of maxilla and buccal aspect of mandible.1,2Their precise designation depends on their respective anatomic locations.3 Wikipedia. The etiology has been studied but no consensus has been reached so far. It is an extension of the bone of the hard palate and and not a true neoplasm. 68. Buccal sided be ignored and carefully should be mandibular angle exostosis - A … Bilateral removal of maxillary posterior exostosis as well as removal of upper left posterior dentition prior to fabrication of a denture. However, these bony structures pose no health concerns and are considered a variation of the normal. A 44-year-old female visited a dentist for a routine checkup. Exostoses. 40 (4):466-468.authors emphasized that rarity of theanatomic site of mandibular lingual 5. The buccal and lingual cusp areas should touch the plane. Buccal Exostosis. MANDIBULAR EXOSTOSIS INTRODUCTION Exostosis, termed torus mandibularis (commonly called mandibular tori), is a common clinical finding. Treatment involves surgical reduction of the bony growth. Torus palatinus is a common developmental exostosis or outgrowth of the bone of the hard palate that manifests itself in adults at about the age of 30. I have buccal exostoses all the way along all of my upper and lower molars, with one particular one being really a problem. Exostoses • Typically buccal posterior • May occur anywhere on alveolus • Adult onset • Bone hard • May interfere with prostheses. Multiple exostosis have long being described in the literature yet there is a continuing paucity in its documentation regarding the incidence and prevalence rates. Eskimo mandible #3. It is usually found along the alveoli or on the hard palate and depending on the location and extent; they can be classified as torus mandibularis (TM), torus palatinus (TP), buccal, or lingual maxillary exostosis. They are less common when compared with mandibular tori. aspect of the mandible, commonly in the canine and premolar areas. 40 (4):466-468. authors emphasized that rarity of the anatomic site of mandibular lingual exostosis involved in this case should not 5. 22 In addition, maxillary tori have been found more frequently in women, and mandibular tori more often in men. Bilateral Maxillary and Mandibular Buccal Exostosis: A Self Reported Case and a Proposal to Include Buccal Exostosis Under Miscellaneous Disorders of Revised Working Classification of the Psychosomatic Disorders Pertaining to Dental Practice. A Technique for Surgical Mandibular Exostosis Removal Author(s): Lee H. Silverstein, DDS, MS, FACD, FICD;Gregori M. Kutzman, DDS Date Added: 10/1/2006. Applicable To. Buccal exostoses, the rarest of the three and seen on the upper molars on the outside of the upper arch (touching the cheek) All of these grow very slowly. Gender: Tori show gender preference, with men more affected by mandibular tori, and palatal tori more common in women. A 44-year-old female visited a dentist for a routine checkup. This is the American ICD-10-CM version of M27.8 - other international versions of ICD-10 M27.8 may differ. Numerous traumatic ulcerative lesions were present because the patient was wearing an ill-fitting mandibular removable partial denture (RPD) replacing teeth Nos. Radiographically, the exostosis appears as an ovoid radiopacity superimposed over the roots of the premolars and molars. Palatal exostoses are similar to buccal exostoses except for location. As the term palatal suggests, a palatal exostosis develops from the lingual aspect of the maxillary tuberosity area. A buccal exostosis is the formation of an exostosis (bone mass) on the outer, cheek-facing side of the maxilla (upper jaw) just above the teeth or the cheek-facing side of the mandible (lower jaw). This article presents a rare case of bilateral maxillary buccal exostosis, distomolars and polydactyly along with surgical management of exostosis. Exostoses of the lingual side … Case 1 22. • Torus palatino: en la línea media del paladar duro. On palpation, the exostoses are hard bony mass. A juvenile mandible with deciduous teeth of Ancylotherium pentelicum (Perissodactyla, Chalicotheriidae, Schizotheriinae), collected by Barnum Brown from the late Miocene of Samos (Greece) Posted on 30.11.2021 by teti Congenital Epulis • Bosselated tumor of the anterior alveolar ridge in newborns • Maxilla > Mandibular ridge • Microscopic: tumor is … Treatment The patient was placed on 500 mg of amoxycillin, one tablet taken three times a day for 10 days, starting the day prior to surgery. Torus and exostosis are bone growth anomalies commonly found on the palate (known as palatine torus), inside of the lower jaw bone (mandibular torus), and outside of either the upper and lower jaw bones (exostosis).They are benign and in most … 67. Buccal exostoses occur as bilateral, smooth bony masses along the buccal aspect of the maxillary and/or mandibular alveolar ridge, usually in the premolar-molar area. Exostosis an exophytic nodular growth of the dense cortical bone, that is present on the buccal surfaces of the maxilla and mandible in the bicuspid and molar region - common in adults Possible risks following buccal exostosis resection include infection, bleeding, swelling and a negative reaction to the anesthesia. Buccal and palatal exostoses are multiple bony nodular masses found less frequently than tori. Sasaki et al determined that prolonged use of Bony Exostosis which are present on buccal aspect of maxilla more common than mandible and thus also called as buccal exostosis. 19 Eskimo mandible #1. Protruding, prominent bone growth is known as exostosis. The spur … Mandibular exostosis is often 10–30% less frequent than the palatal one in the same population, while buccal and lingual maxillary exostoses are very rarely observed. M27.8 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Buccal and palatal exostoses are multiple bony nodules that occur less frequently than tori.1,2,4 Buccal exostoses occur along the buccal aspect of the maxilla or mandible, usually in the premolar and molar areas. The buccal exostosis may remain unnoticeable until they gain in size. Footnote: Lateral radiograph of ankles showing bony enlargement at the posterosuperior aspect of both calcaneum [Source 61)] Buccal exostosis. A bony lump on your gums, therefore, is a dental torus. Exostoses are protuberances of calcified bone which are designated according to typical anatomic location. 66. torus palatinus, buccal maxillar exostosis, or lingual maxillar exostosis. Commonly found to appear in the premolar-molar region. Mandibular exostosis is a type of bony prominence caused due to hyperostosis in the mandibular bone. What Are Tori? Osteochondroma, also known as osteocartilaginous exostosis is a benign cartilage forming tumor that usually develops in long bones and relatively uncommon in the craniofacial region. 24 Same tori in 1998. It is benign and rarely needs treatment. This is the American ICD-10-CM version of M27.8 - other international versions of ICD-10 M27.8 may differ. There are a number of examples of exostoses that occur due to local irritant stimuli: ivory exostosis. Their size may increase to several centimeters, causing food lodgement. They begin to develop in early adulthood and may very slowly enlarge over the years. Why would a discussion of mandibular tori start with a quick anatomy lesson? Buccal and palatal exostoses are multiple bony nodules that occur less frequently than tori.2-4 Buccal exostoses occur along the buccal aspect of the maxilla or mandible, usually in the premolar and molar areas. A buccal exostosis is an exostosis (bone prominence) on the buccal surface (cheek side) of the alveolar ridge of the maxilla or mandible. The mandibular torus is found only on the lingual surface of the mandible, near the bicuspid teeth. exostosis of the external auditory canal (surfer's ear) subungual exostosis. However, the occurrence of exostosis in the buccal aspect of … Mandibular exostosis is often 10-30% less frequent than the palatal one in the same population, while buccal and lingual maxillary exostoses are very rarely observed. A 24-year-old female presented with gingival enlargement on the buccal aspect of both the quadrants of the maxillary arch. A buccal exostosis is an exostosis (bone prominence) on the buccal surface (cheek side) of the alveolar ridge of the maxilla or mandible.Bone is thought to become hyperplastic, consisting of mature cortical and trabecular bone with a smooth outer surface. Buccal exostoses are benign bilateral, smooth surface growth occurring on the outer or facial surface of the maxilla and less commonly, the mandible, found usually in the premolar and molar region 62).The cause is still not established, … mandibular tori and buccal exostoses should be removed. But sometimes, even a small growth can cause a lot of pain. Torus Mandibularis: A bony exostosis on the lingual aspect of the mandible, generally in the premolarmolar region; commonly bilateral. When the exostosis is covered with cartilage, it's called an osteochondroma. Exostosis is a bone spur or outgrowth from the surface of a bone. It is benign and rarely needs treatment. I also have really large mandibular tori inside my lower jaw. an exostosis on the buccal surface of the alveolar ridge of the Buccal bony exostoses have been reported secondary to soft tissue graft procedures and free gingival grafts 7,8 with periosteal trauma seemingly the main etiologic agent. It is an extension of the bone of the hard palate and and not a true neoplasm. 1, 2, 4. Buccal exostoses occur as bilateral, smooth bony growth along the facial aspect of the maxillary and/or mandibular alveolus. Both the condyle and coronoid tip being the most common sites of occurrence in the mandible, it rarely appears at the symphysis region. In this type of exostosis, there is an abnormal growth of the bone that forms the sinus cavity. The prevalence of buccal exostoses varies among studies, most likely because of racial and ethnic differences, with higher rates seen in Mongoloids than in Caucasoids. Etiology is still not established, but it has been suggested that the bony overgrowth can be because of abnormally increased masticatory forces to the teeth. Multiple exostoses classically occur as a series of discrete volume increases in bone along the buccal view of the maxilla and mandible . Buccal exostosis is benign, broad-based surface masses of the outer or facial aspect of the maxilla and less commonly, the mandible. When found on alveoli, exostosis occurs most frequently and tends to be thickest next to molars, … They are often the result of some trauma or injury to the gums and bones underneath. In the entire sample, torus location was the palate in 65% of cases, the mandible in 10.5%, palate and mandible in 14%, maxillary exostosis in 4.4%, exostosis and palate torus in 3.6%, mandibular exostosis in 1.7% and a combination of exostosis and palate and mandibular tori in 0.8%. Called exostoses when there's more than one bony exostosis, they can be found anywhere in the body. Picture of Buccal Exostosis of the Mandible. The palatal torus is found only in the midline of the hard palate. The mandibular torus is found only on the lingual surface of the mandible, near the bicuspid teeth. The buccal exostosis is found only on the facial surface of the alveolar bone, usually the maxillary alveolus. Etiology is still not established, but it has been suggested that the bony overgrowth can be because of abnormally increased masticatory forces to the teeth. Exostoses and tori. Summary: Exostosis, a slow-growing, benign bony outgrowth, is a common clinical … Diagnosis. The presence of buccal exostosis can be diagnosed by both clinical examination and radiological interpretation of the oral cavity. Clinically, buccal exostoses appear as single, broad-based masses, usually situated bilaterally in the premolar and molar region on the facial surface of the maxillary alveolar bone. EXOSTOSIS. Buccal exostosis is Begin, smooth, broad-based bony growth on the facial aspect of maxilla or mandible. A 24-year-old female presented with gingival enlargement on the buccal aspect of both the quadrants of the maxillary arch. Such lesions include buccal exostosis, which arises from the buccal cortex of the maxilla; torus mandibularis, which arises above the mylohyoid line, along the lingual surface of the mandible; torus palatinus, which arises from the midline hard palate; and torus maxillarus, which arises from the lingual surface of the posterior maxilla . Buccal exostosis. Exostosis is a bone spur or outgrowth from the surface of a bone. They … Exostosis can affect any bone, including the knee and heel of the foot. Torus palatinus is often a singular growth, whereas torus mandibularus and buccal exostoses tend to be bilateral, meaning they happen on both sides of the mouth. the lingual aspect of the mandible, usually bilaterally, at the canine-premolar area, above the mylohyoid line. Oral examination revealed bony masses on the buccal alveolar bone in both the maxilla and mandible. After much research I came up with 41823 Excision of osseous tuberosities, dentoalveolar structures...it is a direct crosswalk of D7471 removal of lateral exostosis maxilla and mandible. A buccal exostosis is an exostosis (bone prominence) on the buccal surface (cheek side) of the alveolar ridge of the maxilla or mandible. At physical examination, multiple exostoses were observed on buccal aspect maxila and mandible (Figure 1A). Most common types of intraoral osseous overgrowths are TP and TM. Classification. Tori. 1994. Buccal exostosis is bony prominence located on buccal side of alveolar ridge of maxilla or mandible. However, the occurrence of exostosis in the buccal aspect of the mandibular canine region is a rare occurrence. Buccal exostosis are broad-based, non-malignant surface growth occurring on the outer or facial surface of the maxilla and/or mandible, found usually in the premolar and molar region.. A buccal exostosis is also termed as alveolar exostosis.It is an exostosis (bone prominence) on the buccal surface (cheek side) of the alveolar ridge of the maxilla or mandible. Exostoses. Exostosis of the mouth or jaw is called buccal exostosis. Buccal sidedexostosis involved in this case should not mandibular angle exostosis - A rarebe ignored and carefully should be case report. Buccal exostoses are hard bony protrusions on the outside of your gums and are less common. The prevalence of buccal exostoses in different studies varies from 0.09% to nearly 19%, probably depending on the diagnostic criteria used and the population studied. Oral examination revealed bony masses on the buccal alveolar bone in both the maxilla and mandible. The bony overgrowth can also be seen on the cheek-facing side of the mandible. Mandibular tori and exostoses can be removed by most general dentists, while a palatal torus is often referred to an oral surgeon when a complete denture is needed. Occlusal view of tori and gold crowns. Tori growth cases. 19, 20, 23 to 26, 28, and 30. No treatment is usually required unless they create esthetic or functional limitations during follow-up; the biopsy is needed only for doubtful … (AAP) Tuberosity: An osseous projection or protuberance. Torus mandibularis or mandibular torus, tori mandibularis for plural, is a sublingual protuberance or a benign bony growth occurring on the mandible lingual side. These asymptomatic exostoses were known by the patient for a long time and had developed for many years. Buccal and palatal exostoses are multiple bony nodules that occur less frequently than tori.2-4Buccal exostoses occur along the buccal aspect of the maxilla or mandible, usually in the premolar and molar areas. Buccal exostosis is a bony overgrowth located on the outer side of the maxilla that is facing the cheek superior to the teeth. La mucosa oral que lo recubre se mantiene intacta. Often you feel no symptoms. Oral surgeon spent 2 hours removing 4 buccal exostosis via 4 separate incisions at 4 separate locations. This form of exostosis is a rare condition that causes bony growths from the jaw, usually inside the mouth in the back of the teeth.
Nickname For Someone With A Short Attention Span, Best Video Player For Iphone 2021, Jordan Shoe Size Conversion, Espn 710 Los Angeles Lineup Changes, Top 100 Talk Radio Shows 2021, Traditional Welsh Cake Recipe, Organic Blood And Bone Fertilizer, The Sun Also Rises Masculinity Quotes, Position Relative Z-index Not Working, Celebrity Gogglebox Cast 2020, How Far Is Utah From Georgia By Plane,
mandibular buccal exostosis 2021