Morsicatio buccarum is a condition characterized by chronic irritation or injury to the
buccal mucosa
The oral mucosa is the mucous membrane lining the inside of the mouth. It comprises stratified squamous epithelium, termed "oral epithelium", and an underlying connective tissue termed '' lamina propria''. The oral cavity has sometimes been des ...
(the lining of the inside of the cheek within the mouth), caused by repetitive chewing, biting or nibbling.
Signs and symptoms
The lesions are located on the mucosa, usually bilaterally in the central part of the anterior buccal mucosa and along the level of the occlusal plane (the level at which the upper and lower teeth meet). Sometimes the tongue or the labial mucosa (the inside lining of the lips) is affected by a similarly produced lesion, termed morsicatio linguarum and morsicatio labiorum respectively.
There may be a coexistent
linea alba, which corresponds to the occlusal plane,
or
crenated tongue
Crenated tongue is a descriptive term for the appearance of the tongue when there are indentations along the lateral borders (the sides), as the result of compression of the tongue against the adjacent teeth.
The oral mucosa in the area of crena ...
. The lesions are white with thickening and shredding of mucosa commonly combined with intervening zones of
erythema
Erythema (from the Greek , meaning red) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not asso ...
(redness) or
ulceration
An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing o ...
.
The surface is irregular, and people may occasionally have loose sections of mucosa that comes away.
Causes
The cause is chronic parafunctional activity of the masticatory system, which produces frictional, crushing and incisive damage to the mucosal surface and over time the characteristic lesions develop. Most people are aware of a cheek chewing habit, although it may be performed subconsciously.
Sometimes poorly constructed
prosthetic teeth may be the cause if the original bite is altered. Usually the teeth are placed too far facially (i.e. buccally and/or labially), outside the "
neutral zone", which is the term for the area where the dental arch is usually situated, where lateral forces between the tongue and cheek musculature are in balance.
Glassblowing
Glassblowing is a glassforming technique that involves inflating molten glass into a bubble (or parison) with the aid of a Blowpipe (tool), blowpipe (or blow tube). A person who blows glass is called a ''glassblower'', ''glassmith'', or ''gaffer'' ...
involves chronic suction and may produce similar irritation of the buccal mucosa.
Identical, or more severe damage may be caused by self-mutilation in people with psychiatric disorders, learning disabilities or rare syndromes (e.g.
Lesch–Nyhan syndrome
Lesch–Nyhan syndrome (LNS) is a rare inherited disorder caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). This deficiency occurs due to mutations in the ''HPRT1'' gene located on the X chromosome. LNS ...
and
familial dysautonomia
Familial dysautonomia (FD), also known as Riley-Day Syndrome, is a rare, progressive, recessive genetic disorder of the autonomic nervous system that affects the development and survival of sensory, sympathetic and some parasympathetic neurons ...
).
Diagnosis
The diagnosis is usually made on the clinical appearance alone, and biopsy is not usually indicated. The
histologic
Histology,
also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vis ...
appearance is one of marked
hyperparakeratosis producing a ragged surface with many projections of
keratin
Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, ho ...
. Typically there is superficial colonization by bacteria. There may be
vacuolated cells in the upper portion of the
prickle cell layer. There is a similarity between this appearance and that of
hairy leukoplakia
Hairy leukoplakia is a white patch on the side of the tongue with a corrugated or hairy appearance. It is caused by Epstein-Barr virus (EBV) and occurs usually in persons who are immunocompromised, especially those with human immunodeficiency v ...
, linea alba and
leukoedema.
In people with
human immunodeficiency virus
The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immun ...
, who are at higher risk of oral hairy leukoplakia, a tissue biopsy may be required to differentiate between this and frictional keratosis from cheek and tongue chewing.
Classification
Morsicatio buccarum is a type of
frictional keratosis.
The term is derived from the Latin words, ''morusus'' meaning "bite" and ''bucca'' meaning "cheek". This term has been described as "a classic example of medical terminology gone astray".
The
(DSM-5)
classifies the condition under "Other Specified Obsessive-Compulsive and Related Disorder" (300.3) as a
body-focused repetitive behavior
Body-focused repetitive behavior (BFRB) is an umbrella name for Impulse control disorder, impulse control behaviors involving Compulsive behavior, compulsively self-injury, damaging one's physical appearance or causing physical injury.
Body-focuse ...
; the DSM-5 uses the more descriptive terms lip biting and cheek chewing (p. 263) instead of morsicatio buccarum.
Treatment
The lesions are harmless, and no treatment is indicated beyond reassurance, unless the person requests it. The most common and simple treatment is construction of a specially made acrylic
prosthesis that covers the biting surfaces of the teeth and protects the cheek, tongue and labial mucosa (an
occlusal splint). This is either employed in the short term as a habit breaking intention, or more permanently (e.g. wearing the prosthesis each night during sleep). Psychological intervention has also been attempted, with some studies reporting negative findings,
while some individuals seem to benefit from behavioral procedures involving
habit reversal training and
decoupling.
Epidemiology
This phenomenon is fairly common, with one in every 800 adults showing evidence of active lesions at any one time. It is more common in people who are experiencing stress or psychological conditions. The prevalence in females is double the prevalence in males, and it is two or three times more prevalent in people over the age of thirty-five.
References
External links
{{Oral pathology
Conditions of the mucous membranes
Oral mucosal pathology
Body-focused repetitive behavior