Definitions-3

No	Term		Definitions
501	Mucopolysaccharidosis		A heterogenous group of metabolic disorder usually inherited in an autosomal recessive fashions characterized by lack of one or more normal enzymes leading to accumulation of these glycosaminoglyans or mucopolysaccharides.
502	Mucopurulent		Consisting of both mucous and pus.
503	Mucormycosis		See zygormycosis
504	Mucositis		Mucosal inflammation.
505	Mucous escape phenomenon or Mucous extravastion phenomenon	Is a common salivary gland cyst resulting from rupture of a salivary gland duct and spillage of mucin in to adjacent tissues.
506	Mucous patch		Lesions of secondary syphilis. See syphilis.
507	Mucous retention cyst		Is an epithelium lined cavity that arises from salivary gland tissue and represents a ductal dilatation or obstruction. Clinical features are similar to mucoceles.
508	Mulberry molars		Berry-like molars, due to atrophy of pulp horns in congenital syphilis.
509	Multilocular		A term used to describe a radiographic appearance of multiple, rounded compartments of locules. These can appear "soap bubble-like" or "honeycomb-like".
510	Multiple endocrine neoplasia syndrome.	Autosomal dominant condition involving the parathyroids, pancreas, thyroid and adrenal with one variant (MEN--IIB) that has an oral manifestation consisting of multiple neuromas on the mucosal surfaces
511	Multiple myeloma		A relatively plasma cell malignancy with multiple bony lesions occurring often in old aged with pathological fractures, radiographically punched out radiolucency and histopathologically as sheet of round blue cell and amyloid deposits.
512	Mumps		An endemic paramyxovirus infection affecting bilateral, salivary glands, spreading through respiratory droplets often in children occurring with fever and malaise. The complications include epididymo-orchitis and meningocephalitis.
513	Munro abscess		A collection of neutrophils inside the epithelium is called as Munro’s abscess and observed in Psoriasis.
514	Mutagenesis		The induction of genetic mutation.
515	Mutation		A permanent change in the arrangement of genetic material.
516	Myelophithisic anemia		An anemia caused by malignant proliferation of leukocytes compressing the normal marrow tissues.
517	Myofibromatosis		See dermatofibromatosis.
518	Myospherulosis		A reactive, foreign body granulomatous reaction to placement of topical tetracycline in a petrolatum base in a surgical site or defect.
519	Myxoma		A much debated aggressive intraosseous lesion derived from embryonic connective tissue associated with odontogenesis and primarily consisting of a mucoid ground substance with widely scattered undifferentiated spindled mesenchymal cells.
520	Nasoalveolar cyst		See nasolabial cyst
521	Nasolabial cyst		A developmental fissural cyst of the soft tissue of the anterior muco-buccal fold beneath the ala of the nose or in the upper lip, most likely derived from remnants of the inferior portion of the nasolacrimal duct.
522	Nasopalatine duct cyst		An intraosseous developmental fissural cyst of the midline of the anterior palate, derived from the islands of epithelium remaining after closure of the embryonic nasopalatine duct. The lesion presents as a heart shaped radiolucent area between maxillary central incisors in a radiograph.
523	Nasopharyngeal angiofibroma		A rare benign neoplasm with vascular and fibrous component occurring in nasopharyngeal region of young males.
524	Nasopharyngeal carcinoma		An aggressive form of squamous cell carcinoma arising from epithelium lining the nasopharynx commonly occurring in Cantonese Chinese and attributed to Epstein –Barr virus.
525	Natal teeth		Refers to those teeth that may be present at birth.
526	Necrosis		The death of a cell as a result of injury or disease.
527	Necrotizing sialometaplasia		An uncommon locally destructive inflammatory condition of the salivary glands resulting from ischemia of the salivary gland tissue that leads to local infraction. It mimics a malignancy in clinical and histopathological presentation.
528	Neonatal teeth		Refers to those teeth that arise within the first thirty days of life are neonatal teeth.
529	Neoplasia		The process of the formation of tumors. See tumor.
530	Neoplasm		See tumor.
531	Neuralgia Inducing Cavitational Osteonecrosis (NICO)		A low grade, non-supparative, osteomyelitis of jaw with poorly visible radiographic features occurring in patients with neuralgic pain.
532	Neurilemmoma		See Schwanomma.
533	Neurofibroma		A common type of peripheral nerve neoplasm, occurring as demarcated or diffuse benign proliferation of perineural fibroblasts that are oriented in either a random pattern with a myxoid background or a nodular (plexiform) pattern.
534	Neurofibromatosis		A common hereditary condition autosomal dominant condition characterized by multiple neurofibromas of various sizes.
535	Neurofibrosarcoma		A malignant counterpart of Neurofibromatosis.
536	Neurogenic sarcoma		Malignant neoplasm with a poor prognosis of perineural fibroblasts or Schwann cells with a propensity to rapidly extend along the associated nerve trunk.
537	Neuroma		A benign tumor of nervous tissue.
538	Neutropenia		A diminished number of neutrophils in the blood.
539	Nevoid basal cell carcinoma syndrome		An autosomal dominant disorder characterized by oral, systemic and skeletal anomalies. An inherited group of defects which involve abnormalities of the skin, eyes, nervous system, endocrine, glands and bones. The condition is characterized by an unusual facial appearance and a predisposition for skin cancer.
540	Nevus		A benign, exophytic, usually pigmented, congenital lesion of the skin or mucosa composed of focal collections of rounded melanocytes; a mole. It may be flat or elevated, pigmented or non-pigmented, and may or may not contain hair.
541	NICO		See Neuralgia inducing cavitational osteonecrosis
542	Nicotine palatinus		See smoker’s palate
543	Nicotine stomatitis		A diffuse, reactive, reversible white change of the buccal mucosa caused by a combination of hyperkeratosis and acanthosis, frequently containing multiple small nodules; found in heavy smokers due to the heat.
544	Nikolsky's sign		A clinical sign observed some bullous diseases, such as pemphigus vulgaris and bullous pemphigoid where the superficial epithelium separates easily from the basal layer on exertion of firm sliding manual pressure.
545	Nodular fascitis		Localized benign lesion composed of fibroblasts and myofibroblasts that are often clinically mistaken for a malignancy.
546	Nodular melanoma		A form of melanoma of the skin and occasionally the mucosa that arises as a raised mass with a limited radial-growth phase quickly invades and metastasizes and consists of a wide variety of cell shapes and sizes.
547	Nodule		A palpable solid lesion greater than 5 mm in diameter found in soft tissue. It can occur above, level with, or beneath the skin surface.
548	Odontogenic cyst		A cyst in which the lining of the lumen is derived from epithelium produced during tooth development.
549	Odontogenic fibroma		A peripheral or intraosseous (central) benign neoplasm derived from connective tissue of odontogenic origin containing widely scattered islands and strands of embryonic odontogenic epithelium and calcifications.
550	Odontogenic keratocyst		A cyst derived from the remnants (rests) of the dental lamina, with a biologic behavior similar to a benign neoplasm, with a distinctive lining of six to ten cells in thickness, and that exhibits a basal cell layer of palisaded cells and a surface of corrugated parakeratin.
551	Odontogenic tumors		Lesions derived from epithelial or mesenchymal elements, or both, that are odontogenic in nature.
552	Odontoma		Are common developmental hamartoma of odontogenic in origin. They are found in children and young adult as painless swelling composed of multiple small tooth like structure (compound) or conglomerate mass of enamel and dentin (Complex).
553	Oligodontia		Absence of six or more teeth than the normal number of teeth.
554	Oncogenic		Capable of causing tumor formation.
555	Oncology		The study of tumors or neoplasms.
556	Opportunistic infection		A disease caused by a microorganism that does not ordinarily cause disease but becomes pathogenic under certain circumstances.
557	Oral submucous fibrosis		Is an insidious chronic disease affecting any part of the oral cavity & sometimes the pharynx. It is always associated with juxta epithelial inflammatory reaction followed by fibroelastic change of lamina propria with epithelial atrophy leading to stiffness of the oral mucosa causing trismus and inability to eat. (WHO, 1967)
558	Ossifying fibroma		A well-demarcated fibro-osseous lesion, encapsulated, expansile intraosseous lesion of the jaws composed of cellular fibrous tissue containing spherical calcifications and irregular, randomly oriented bony structures.
559	Osteoblastoma		A benign neoplasm of bone that arises from osteoblasts with similar clinical, radiographic, and histopathologic features of osteoid osteoma consisting of well-demarcated, rounded intraosseous swellings, each with an active cellular central nidus surrounded by a wide zone of osteoid, with pain upon palpation.
560	Osteogenesis imperfecta		A spectrum of diseases of bone due to a basic alteration in the formation of bone connective tissue matrix, resulting in an inability of the matrix to fully mineralize exhibiting a tendency for multiple broken bones, blue sclera of the eyes and associated dentinogenesis imperfecta.
561	Osteoma		An exophytic nodular growth of dense cortical bone on or within the mandible or maxilla in locations other than those occupied by tori or exostoses.
562	Osteomyelitis		An inflammatory process within medullary (trabecular) bone that involves the marrow spaces.
563	Osteopetrosis		Generalized hereditary condition consisting of excessive bone mineralization, resulting in altered stature, frequent fractures, lack of bone marrow hematopoietic function, and a tendency for severe osteomyelitis of the jaws.
564	Osteoradionecrosis		A condition of non-vital bone in a site of radiation exposure due to hypoxia hypocellular and hypovascular bone.
565	Osteosclerosis		Abnormal hardening or increased density of bone on radiographs.
566	Paget’s disease		An osteodystrophy characterized by uncoordinated bone remodeling of adults producing larger but weaker bones, extensive pain, high levels of serum alkaline phosphatase and urinary hydroxyproline, and an increased tendency for pathological fractures and develop malignant bone neoplasm.
567	Palpation		The evaluation of a lesion by feeling it with the fingers to determine the texture of the area. The descriptive terms for palpation are soft, firm and fluid filled. These terms also describe the consistency of a lesion.
568	Papillary		A term describing a small numerous projection usually found in clusters.
569	Papillary hyperplasia		A reactive tissue growth that usually develops beneath an ill fitting upper denture.
570	Papilloma		A benign exophytic papillary growth of stratified squamous epithelium. Most common epithelial pathology. Often caused by Papilloma virus.
571	Papillon Lefevre syndrome		An autosomal recessive disorder characterized by severe destructive periodontal disease affecting both the primary and permanent dentitions and hyperkeratosis of the palms of the hands and soles of the feet due to an immune defect.
572	Paradental cyst		An odontogenic cyst of uncertain origin found primarily on the distal or facial aspect of a vital mandibular third molar, consisting of intensely inflamed connective tissue and epithelial lining.
573	Parakeratin		An epithelial component of keratosis which has small residual nuclei in the superficial corneal layer.
574	Parulis		A sessile nodule on the gingiva at the site where draining sinus tact reaches the surface.
575	Pathogenesis		A series of events taking place in a disease leading to the presentation of complaint.
576	Pavementing		The process of adherence of leukocytes to the endothelial cells lining an injured blood vessel.
577	Pedunculated		Attached by a stem-like or stalk base similar to that of a mushroom. Or The narrowest part of the lesion is attached to the surface.
578	Pellicle		The thin covering on the surfaces of teeth derived from the salivary proteins. When microorganisms colonize this pellicle it is termed as plaque.
579	Penetrance		The prevalence of individuals with a given genotype that manifest clinically the phenotype associated with that trait.
580	Periapical abscess		A sequale of chronic pulpitis in which there is an exudates collection extending into the adjacent periapical tissues.
581	Periapical cemental dysplasia		Asymptomatic diffuse periapical radiolucent and radiopaque areas in which cemento-osseous tissue replaces the normal architecture of bone.
582	Periapical cyst		An inflammatory odontogenic cyst of preceded by a chronic periapical abscess or a granuloma with epithelium derived from rests of Malassez present in the periodontal membrane usually as a result of dental caries.
583	Periapical granuloma		A mass of chronically inflamed granulation tissue resulting from irritation following pulp disease or endodontic treatment at the tip of the root.
584	Pericornitis		An inflammatory lesion caused by the accumulation of food debris in a soft tissue space between erupting teeth and the alveolar mucosa covering it and subsequent infection of  gram negative organism. Common in mandibular third molars.
585	Periodontal abscess		A localized accumulation of puss with in periodontal pockets is called as a periodontal abscess.
586	Periodontal pocket		The pathological space between the tip of the free gingiva and the base of the sulcular epithelium at the cementum filled by plaque, food debris and microbes.
587	Peripheral		Pertaining to the outer part, such as the edge or margin.
588	Peripheral ossifying fibroma		A benign reactive lesion that occurring exclusively on the gingiva with areas of ossification or cementum. (Peripheral cemento –ossifying fibroma).
589	Pernicious anemia		An anemia caused by deficiency of Vitamin B12 and intrinsic factor causing macrocytic and hyperchromic type of RBC.
590	Petechiae		Little red spots, ranging in size from pinpoint to several millimeters in diameter. Petechiae consist of extravasated blood within an intact mucosa.
591	Phagocytosis		A process of ingestion and digestion by leukocytes.
592	Phenotype		The physical and clinical visible characteristics of an individual and is genotype’s observable appearance.
593	Phoneix abscess		An exacerbation of a chronic lesion is called as a phoenix abscess.
594	Pigmented		Colored as the result of a deposit of pigment exogenous or endogenous.
595	Pindborg tumor		See Calcifying epithelial odontogenic tumor
596	Plaque		An area with a flat surface and raised edges.
597	Plaque		Is a complex microbial ecosystem found on the hard surfaces of oral cavity and is composed of salivary proteins, food debris, desquamated epithelial cells and microbes. Plaque is the common cause of gingivitis.
598	Platelet		One of the formed elements found in circulating blood. A platelet has a circular or disk-like shape is small. Platelets aid in blood coagulation and clot retraction.
599	Pleomorphic		Occurs in various forms.
600	Polycythemia		An increase in the total red blood cell mass in the blood.
601	Polyostotic fibrous dysplasia		Fibrous dysplasia affecting several or many bones and café au lait spots. Can be classified in to Jaffe type and Mc Cune Albright Syndrome.
602	Port wine stain		A unique type of Hemangioma consisting of superficial and deep dilated capillaries in the skin which produces reddish to purplish discoloration of the surface skin.
603	Potentially malignant condition (Previously Premalignant condition)		A disease or a habit that does not necessarily alter the clinical appearance of the local tissue but is associated with a greater than normal risk of cancer development in that tissue.
604	Potentially malignant lesion (Previously Premalignant lesion)		A benign, morphologically altered tissue that has a greater than normal risk of malignant transformation.
605	Primary intra osseous carcinoma		A squamous cell carcinoma within bone and with no indication that it originated from surface epithelium or that it metastasized from another site.
606	Primary tumor The original tumor; the source of metastasis.
607	Proliferation		The multiplication of cells.
608	Proliferative verrucous leukoplakia		A distinct potentially malignant lesion characterized by diffuse white and/ or papillary area of the mucosa caused by varying degrees of epithelial hyperplasia; it has the potential to develop into verrucous carcinoma or well-differentiated squamous cell carcinoma.
609	Prosoplasia		Is an irreversible change in which one adult cell type is replaced by another type.
610	Proteolytic – chelation theory		It states that Dental caries is a simultaneous process of microbial degradation of organic components and dissolution of minerals by chelation that is independent of pH.
611	Proteolytic theory		It states that dental caries initiates at the organic or protein elements through which bacteria enters and cause the lyses of soft and hard tissues of teeth.
612	Pseudoepitheliomatous hyperplasia		An excessively elongated rete pegs composed of normal keratinocytes that extend into the immediately adjacent connective tissue, giving a false impression of a squamous cell carcinoma seen in a variety of conditions.
613	Pulp stone		Calcification within the dental pulp lying free or attached to the pulpal surface of the tooth.
614	Pulpal abscess		An inflammation of the dental pulp, associated with a localized collection of necrotic tissue and pus arising from breakdown of leukocytes and bacteria, sometimes walled off with connective tissue.
615	Pulpitis		An inflammation of the pulpal tissue that may be acute or chronic with or without symptoms and reversible le or irreversible.
616	Purpura		A group of platelet disorders characterized by purplish or brownish-red discolorations caused by bleeding into the skin or tissues.
617	Purulent		Containing pus.
618	Pustule		Blisters of various sized circumscribed elevations containing pus.
619	Pyogenic granuloma		A benign reactive lesion restricted to gingiva characterized by a fast-growing proliferation of endothelial cells and usually in response to chronic irritation.
620	Pyronine bodies		Are clusters of lightly basophilic particles in association with plasmacytic infiltrate in periapical granuloma.
621	Quincke’s disease		See angioneurotic edema.
622	Radiation therapy		The careful use of high-energy radiation to treat cancer either in conjunction with surgery or chemotherapy or alone.
623	Radicular cyst		An odontogenic cyst of inflammatory origin that is preceded by a chronic periapical granuloma and stimulation of rests of Malassez present in the periodontal membrane.
624	Radiolucent		The black or dark areas in a radiograph that result from the ability of radiant energy to pass through the structure. Less dense structures (e.g., the pulp) are radiolucent.
625	Radiopaque		The white or clear appearance in a radiograph that results from the inability of radiant energy to pass through a structure. The more dense the structure (i.e., amalgam restorations), the whiter it appears in the radiograph.
626	Rampant Caries		A rapidly spreading type of caries commonly seen in bottle feeding children occurring in areas that is less prone for caries.
627	Ramsay Hunt syndrome		Is a combination of cutaneous lesions of herpes zoster of external auditory canal with involvement of ipsilateral facial paralysis and auditory nerves.
628	Ranula		Is a term used for mucocele occurring in the floor of mouth.
629	Ratner bone cavity		See NICO
630	Raynaud’s phenomenon		A phenomenon exhibited by persons exhibited to cold. From blanching of the digits to the blue color due to venous stasis the color change is observed.
631	Recessive In genetics, a trait or characteristic manifested clinically with a double gene dose in autosomic chromosomes or with a single dose in males if the trait is X-linked.
632	Reed- Sternberg cells		See Doorthy Reed cells
633	Regional odontodysplasia		A developmental disturbance of several adjacent teeth in which the enamel and dentin are thin and irregular and fail to adequately mineralize; surrounding soft tissue is hyperplastic and contains focal accumulations of spherical calcifications and odontogenic rests.
634	Repair		The restoration of damaged or diseased tissues.
635	Residual cyst		A cyst that remains at the site of a previously extracted tooth.
636	Retention cyst		See Mucocele
637	Retrocuspid papilla		A sessile nodule on the gingival margin of the lingual aspect of the mandibular cuspids.
638	Reverse smoking		A peculiar smoking habit practiced by certain people all over world, (Andhra Pradesh in India) where the lighted end is held inside the mouth.
639	Reversible pulpitis		Mild inflammation of the tooth pulp caused by dental caries or trauma to the pulp, the changes being reversible once the trauma is removed.
640	Rhabdomyoma		A rare, benign neoplasm of striated muscle.
641	Rhabdomyosarcoma		Rare, rapidly growing malignant neoplasm of striated muscle that occurs in three histologic patterns (embryonal, alveolar, and pleomorphic) having a poor prognosis.
642	Rheumatoid factor		A protein, an immunoglobulin M (IgM), found in serum and detectable on laboratory tests. It is associated with rheumatoid
643	Riga- Fede disease		A chronic type of traumatic ulceration that is histopathologically unique exhibiting a deep pseudoinvasive inflammatory reaction with high number of eosinophilia, also similar to “TUGSE”. The Lesion is seen in nursing babies when lower teeth erupt to cause ulcerations at the ventral surface of tongue and rarely on dorsal surface by the maxillary incisors.
644	Rodent ulcer		See basal cell carcinoma
645	Romberg syndrome		A characteristic loss in the soft tissues below the skin, usually on one side of the face; In some severe cases, the underlying bone is also effected.
646	Root resorption		Breakdown or destruction of root structure; loss of root structure. The apex of the tooth appears shortened or blunted and irregularly shaped.
647	Rootless teeth		A hereditary defect in dentin formation in which the coronal dentin and tooth color is normal; the root dentin is abnormal with a gnarled pattern and associated shortened and tapered roots.
648	Russell bodies		Are scattered eosinophilic globules of gamma globulin secreted by numerous plasma cells seen in periapical granuloma.
649	Saint Anthony’s fire		Earlier name of Erysipelas, an infection of skin caused by streptococcus, spreading through lymphatics as red well circumscribed indurated areas occurring in children.
650	Salivary Calculi		Refers to calcified structures that develop within the salivary ductal system, by deposition of calcium salts around a nidus of debris within the lumen.
651	San Joaquin Valley fever		Is the other name of coccidiomycosis.
652	Sarcoidosis		Is an insidious multisystemic granulomatous disorder of unknown cause in middle aged individuals with symptoms similar to tuberculosis with scattered nonspecific tender erythematous nodules called erythema nodosum.
653	Sarcoma		Malignant growth of connective tissues origin.
654	Scalloping		A margin that is not straight or smooth; with periodical up and downs.
655	Scarlet fever		Is a systemic infection produced by beta hemolytic group of streptococci that begins as a tonsillitis and pharyngitis and produces an enanthematous and exanthematous reaction via an erythrogenic toxin. Common in children.
656	Schaumann bodies		The granulomatous inflammation of sarcoidosis contains a laminated basophilic calcifications called as schaumann bodies.
657	Schwannoma		Well-demarcated, benign neural lesion consisting of a fibroblastic proliferation of the nerve sheath cell (Schwann cell) producing distinctive patterns referred to as Antoni A, Antoni B tissue and Verocay bodies.
658	Scleroderma		A rare immunologically mediated dermatologic abnormality leading to Raynaud’s phenomenon or CREST syndrome with skin developing a diffuse, hard texture with a smooth surface.
659	Scrofula		A form of tuberculosis spread through infected milk presenting as a enlargement of oropharyngeal lymphoid tissue with cervical lymph node involvement.
660	Scrotal tongue		See fissured tongue
661	Scurvy		A bleeding gingival status caused by vitamin C deficiency status due to faculty collagen synthesis mechanism.
662	Sebaceous cyst		Is a common cyst of skin with a lumen lined by keratinizing stratified squamous epithelium, usually filled with keratin and without skin appendages in the capsule wall.
663	Sequestrum		A fragment of dead bone separated from healthy bone as a result of chronic inflammation or infection.  .
664	Serous		A substance having a watery consistency; relating to serum.
665	Sessile		When the broadest part of the lesion is attached to the surface of the body it is said to be sessile. Describing the base of a lesion that is flat or broad.
666	Shagreen patches		A skin hamartoma lesion observed in trunk of patient with tuberous sclerosis that resemble skin of shark.
667	Shell teeth		In severe form of dentinogenesis imperfecta, due to pulpal enlargement, thin dentin and normal enamel commonly associated with deciduous dentition.
668	Shingles		See Herpes zoster
669	Sialadenitis		Refers to the inflammation of the salivary glands which can arise from various infectious and non infectious cause, the most common being mumps.
670	Sialolithiasis		See salivary calculi
671	Sialo-odontogenic cyst		An unusually large solitary or multilocular odontogenic cyst probably derived from the rests of dental lamina, consisting a stratified squamous epithelium containing numerous mucus-secreting cells.
672	Sickle cell anemia		Is a hemoglobinopathies, a genetic disorder because of the mutational substitution of thymine for adenine in DNA, resulting in valine than glutamic acid in beta chain of globin turning the hemoglobin to be more prone for aggregation and polymerization in deoxygenated state.
673	Sideropenic dysphagia		See Plummer – Vinson syndrome
674	Sign		A feature of the disease or condition elucidated by the examining physician by performing palpating or auscultations.
675	Sinus tract		A pathological drainage pathway from a deep focus of acute infection through tissue and/or bone to an opening on the surface.
676	Sjogren’s syndrome		The chronic, systemic autoimmune disorder that principally involves the salivary, lacrimal and eyes is the Sjogren’s syndrome.
677	Smoker´s melanosis		A reactive, irregularly shaped brownish macular pigmentations of oral tissue that are associated with prolonged tobacco smoking.
678	Smoker’s palate		A reactive white keratotic patch that commonly develops in palate in reaction to the heat of tobacco smoke appearing as numerous papules often grayish white in color with punctuate red centers. It is not a potentially malignant state.
679	Snuff dipper’s lesion		Is a reactive change in mucosa to the chronically placed smokeless tobacco appearing as a whitish or grayish white velvety lesion.
680	Somatic cells		All the cells of the human body with the exception of the germ cells.
681	Sphenopalatine neuralgia		Is a paroxysmal intense painful condition affecting the mid and upper face of unknown etiology. The pain attacks over a period of few weeks followed by period of remission to recur.
682	Spindle cell carcinoma or Carcinosarcoma		Rare, unusual form of poorly differentiated squamous cell carcinoma consisting of elongated (spindled) epithelial cells that resemble a sarcoma.
683	Spitz nevus		Is an uncommon type of small melanocytic nevus that share many histopathological features with melanoma occurring during childhood.
684	Squamous cell carcinoma		A malignant neoplasm of stratified squamous epithelium that is capable of locally destructive growth and distant metastasis.
685	Squamous odontogenic tumor		A rare, sometimes multifocal, potentially aggressive lesion derived from odontogenic epithelium, consisting of islands of stratified squamous epithelium that commonly contain microcysts and calcifications in a dense fibrous background.
686	Stafne cyst or Stafne defect		A developmental concavity of the lingual cortex of the angle of mandible, caused by overextension of an accessory lateral lobe of the submandibular gland, and has the radiographic appearance of a well-circumscribed cystic lesion within the bone, usually below the inferior alveolar canal
687	Stain		A deposit on the hard tissue surface of oral cavity characterized by a color change.
688	Stevens-Johnson syndrome		A severe form of erythema multiforme triggered by a drug reaction often involving the ocular, genital mucosa in conjunction with oral and skin lesion.
689	Struge – Weber syndrome		A rare non hereditary developmental condition characterized by a hamartomatous vascular proliferations and neurological abnormalities.
690	Stylohyoid syndrome		See eagle syndrome
691	Superficial spreading melanoma		Most common form of malignant melanoma, initially appearing as an irregularly shaped brown-black macular area with jagged borders and satellite lesions in which areas of nodular melanoma eventually develop.
692	Supernumerary		One or more than the normal complement.
693	Surgical ciliated cyst of maxilla		An intrabony cyst located near or at the floor of the maxillary sinus lined by pseudostratified ciliated columnar respiratory epithelium, caused by implantation of normal mucus-secreting sinus epithelium during previous surgery or a trauma including traumatic extraction.
694	Sutton’s disease		Is the Major apthous ulcer with long episodes, deep and heals with scarring.
695	Swift disease		See Acrodynia
696	Symptom		A manifestation of disease of which the patient is usually aware and frequently complains.
697	Syndrome		A combination of signs and symptoms occurring commonly enough to constitute a distinct clinical entity.
698	Syphilis		Is a sexually or vertically transmitted, world wide, chronic, granulomatous infection produced by Treponema palladium. The primary and secondary stages may be infective when occurring in oral cavity.
699	Systemic		Pertaining to or affecting the body as a whole.
700	Systemic lupus erythematosus		Is a immunologically mediated multisystemic disease often involving skin, kidney and cardiac complications.
701	Systemic sclerosis		See Scleroderma.
702	T lymphocyte		A lymphocyte that is differentiated in the thymus before migrating to tissues. The T lymphocyte, also called a T cell, is responsible for cell-mediated immunity.
703	Talon cusp		A developmental defect in the shape of teeth that is form of supernumerary cusp which arises from the cingulum portion of the tooth and extends to the incisal edge as a prominent projection of enamel that imparts a T shape, usually of incisors and canine.
704	Target lesion		A concentric circular erythematous rings resembling a targets or bull’s eye as observed in the immunologically mediated erythema multiforme.
705	Taurodont		A developmental abnormality of a malformed multirooted tooth characterized by an altered crown-to-root ratio, the crown being of normal length, the roots being abnormally short, and the pulp chamber being abnormally large.
706	Tay-Sach’s disease		A lipid reticuloendothelioses inherited as autosomal recessive trait caused by a lack of hexosaminadase A that results in accumulation of ganglioside within lysosome of neurons.
707	Telangiectasia		The formation of small dilated capillaries near the surface of a tissue. Telangiectasia may be a sign of hereditary disorder, alcohol abuse, or malignancy in the region.
708	Temporal arteritis		Is an idiopathic, multifocal vasculitis of cranial arteries (superficial temporal artery) presenting as a unilateral throbbing headache characterized by the chronic inflammation of intima and tunica media of the arteries, narrowing of lumen and edema and proliferation of intima.
709	Teratoma		A developmental tumor composed of tissue from all three germ layers and believed to arise from germ cells or entrapped totipotent blastomeres.
710	Thalassemia		Represents a group of inherited disorders of hemoglobin synthesis characterized by reduced synthesis of beta globin chains of hemoglobin molecule. If only one gene is affected it is a minor form and if both genes are affected it is major form of thalassemia.
711	Thrombocyte		A platelet.
712	Thrombocytopenia		Decrease in the number of platelets in circulating blood due to many pathological conditions.
713	Thrush		See candidiasis
714	Thymus		A lymphoid organ that is situated in the retrosternum. It reaches maximal development at about puberty and then undergoes gradual involution.
715	Thyroglossal duct cyst or Thyroglossal tract cyst		A developmental midline, painless, fluctuant, movable cyst arising from remnants of thyroglossal duct epithelium.
716	Tic douloureux		See trigeminal neuralgia.
717	Tobacco pouch keratosis		A reactive altered mucosa due to use of smokeless tobacco usually in mandibular vestibule or in the area of the placement of smokeless tobacco. The alteration disappears with the discontinuation of the habit.
718	Tooth discoloration		Color changes in the teeth.
719	Tori or Torus		A benign bony nodule on the hard palate or on the lingual aspect of the premolars area of mandible.
720	Toxic epidermal necrolysis		A most severe form of erythema multiforme, mostly triggered by a drug exposure causing a diffuse sloughing of mucosal and skin surface in older people.
721	Translucent		Somewhat penetrable by rays of light.
722	Trauma		A wound or injury; damage produced by an external force.
723	Traumatic bone cyst		Asymptomatic intraosseous empty cavity of young patients located primarily within the jaw bone, lined by a thin loose connective tissue membrane and is adequately treated when blood enters the space during an intraosseous biopsy.
724	Traumatic neuroma		A benign painful nodular proliferation of nerve and fibrous tissue of the nerve sheath resulting from the futile attempt of nerve fibers to reunite with their severed distal portion due to a trauma.
725	Traumatic neuroma		A painful reactive proliferation of neural tissue at a site of injury
726	Traumatic Ulcerative Granuloma with Stromal Eosiophilia (TUGSE)		See Riga –fede disease.
727	Treacher Collins syndrome		An autosomal dominant inherited first and second branchial arch abnormality characterized by slanting palpebral fissures, sunken cheek bones, receding chin, and malformed ears.
728	Trench mouth		See ANUG
729	Trigeminal neuralgia		An unexplained pain in the peripheral parts of the fifth cranial nerve causing a sharp intense lancinating pain for a shorter duration occurring in episode separated by a refractory period and has trigger zone.
730	Trisomy		A pair of chromosomes with an identical extra chromosome.
731	Tubercle		The granuloma of tuberculosis made up of circumscribed collection of epithelioid histiocytes, lymphocytes and multinucleated giant cells with a central caseous necrosis is called as tubercle.
732	Tuberculosis		A chronic debilitating bacterial infection caused by Mycobacterium tuberulosis, causing a cell mediated hypersensitivity reaction with evening raise of fever, loss of weight and chronic cough.
733	Tuberous sclerosis		An autosomal dominant inherited uncommon syndrome characterized by mental retardation, seizure and angiofibromas.
734	Tumor		An abnormal mass of tissue the growth of which is uncoordinated with that of the normal tissue and does not cease when provoking stimulus are removed.
735	Turner’s hypoplasia or Turner’s tooth		Enamel hypoplasia of a single tooth, most commonly one of the permanent maxillary incisors or a maxillary or mandibular premolar, resulting from local infection or trauma.
736	Tyndall effect		Refers to the interaction of light with particles in colloidal solution producing the blue color of blue nevus.
737	Tzanck cells		The acantholytic epithelial cell with nucleolar fragmentation with condensation of chromation around the periphery of the nucleus. Seen in Viral infection like herpes and pemphigus vulgaris.
738	Ulcer		A loss in continuity of surface epithelium that extends in to lamina propria. The cause of ulcer is many and usually due to a sloughing of necrotic inflammatory tissue.
739	Unilocular		A term used to describe a radiographic appearance of a single, rounded compartment or locule.
740	Varicella Or chicken pox		Is a common viral infection in children caused by varicella zoster or human herpes virus -3, spread through air droplets or direct contact and causes intensely pruritic exanthema that characteristically is observed as “a dewdrop on a rose petal” after which they ulcerate to heal.
741	Varicosity or Varicies		Is an abnormally dilated and tortuous vein commonly observed in aged due to the loss in the rigidity of the vessel wall.
742	Ventral		Directed toward or situated on the belly surface in humans (opposite of dorsal).
743	Verocay bodies		In neurilemoma, the neural tissue is regularly arranged in streaming fascicles of schwan cells which form a palisaded arrangement around central, acellular, eosinophilic areas called as verocay bodies.
744	Verruca vulgaris		Is a benign viral induced (HPV-2, 4, 40) hyperplasia of stratified squamous epithelium that appears as a painless papule or a nodule with a papillary projections.
745	Verruciform xanthoma		A well demarcated, soft, painless, sessile, epithelial hyperplastic condition of unknown etiology characterized by an accumulation of lipid laden histiocytes in the connective tissue papillae.
746	Verrucous carcinoma		A distinct, diffuse, papillary, superficial, locally invasive, usually non-metastasizing form of low grade well-differentiated squamous cell carcinoma occurring in aged.
747	Verrucous hyperplasia		The papillary exophytic proliferation with increase in thickness of epithelium in a hyperkeratotic whitish unscrappable patch is referred as verrucous hyperplasia.
748	Verrucous leukoplakia		A nodular leukoplakia that is exophytic and demonstrates verrucous projections is referred as verrucous leukoplakia.
749	Vesicle		A well-defined lesion of the skin and mucous membranes that resembles a sac, contains fluid, and is less than 1 cm in diameter.
750	Vincent’s infection		See ANUG
751	Visceral		Pertaining to body organs.
752	Von Recklinghausen´s disease		An autosomal dominant hereditary condition with a mutation in 17q11.2 with an abnormal neurofibrin, presenting as multiple neurofibromas of the skin and mucosa and associated café au lait spots of the skin with the potential for producing disfigurement and malignant transformation.
753	Wart, Common		Is a benign viral induced (HPV-2, 4, 40) hyperplasia of stratified squamous epithelium that appears as a painless papule or a nodule with a papillary projections
754	Wart, Veneral		Is a virus induced (HPV 6, 11, 16, 18) proliferation of the stratified squamous epithelium of the genetilia.
755	Warthin’s Tumor		Is a benign neoplasm of parotid salivary gland that presents as a slowly growing painless nodular mass and is composed of a mixture of ductal epithelium and a lymphoid stroma.
756	Warty dyskeratoma		Is an uncommon solitary, asymptomatic, umblicated papule of the skin the histopathology of which is very similar to that of Darier’s disease.
757	Wegener’s granulomatosis		A well recognized uncommon disease process of unknown cause with multi organ involvement with a characteristic oral change of strawberry gingivitis and or oral ulcerations.
758	Well circumscribed		A term used to describe a lesion whose borders are specifically defined, and in which one can clearly see the exact margins and extent
759	White sponge nevus		Relatively rare autosomal dominant hereditary condition in which the oral mucosa has a pearly white, thickened and folded. High penetrance and variable expression.
760	Whitlow		A herpes infection involving the distal phalanx of a finger. Commonly seen in dentist.
761	Wickhams striae		They are the characteristic fine lacy white lines observed in the lichen planus.
762	Xanthoma cells		These are the numerous large macrophages with foamy cytoplasm confined to connective tissue papillae that contain lipid, diastase resistant granules.
763	Xeroderma pigmentosum		A rare autosomal recessive trait genodermatosis that predisposes to malignancies. The defect lies in the excision repair and or post replication mechanism of DNA.
764	Xerophthalmia		Abnormal dryness of the eyes as observed in condition like Sicca syndrome.
765	Xerostomia		It is a condition of dry mouth. The cause of dry mouth could be local, systemic or psychogenic factors. With true xerostomia the quantity and or quality of saliva are diminished.
766	Zoster sine herpete		It is a type of herpes zoster that is recurrent and occurs with the absence of vesiculation of the skin or mucosa.
767	Zygomycosis		An Opportunistic, frequently fulminant, fungal infection that is caused by normally saprophytic organisms of the class Zygomycetes including Absidia, Mucr, and Rhizopus. The disease frequently affects immunocompromised and diabetics. Rhinocerebral form of the disease is of interest to the dentist.