CIRCLE OF WILLIS(Circulus arteriosus cerebri)

The only weapon with which the unconscious patient can immediately retaliate upon the incompetent surgeon is hemorrhage -William S Halsted.

Also known as loop of Willis,Willis polygon and cerebral arterial circle.

Blood vessels supplying the brain consists of 2 separate vascular systems:

  • Internal carotid arteries
  • Vertebral arteries

In the base of the brain both systems are connected bilaterally by posterior communicating arteries and left to right side by anterior communicating arteries forming the “Circle of Willis”(COW).

Other key points:

  • In subclavian steal syndrome ,blood is “stolen” from COW to preserve blood flow to upper limb.
  • This syndrome results from a proximal stenosis of the subclavian artery.
  • Variations in the shape of COW is also seen in mentally ill and migraine patients which include hypoplasia of component vessels,absence of posterior communicating arteries,duplication/triplication of anterior communicating arteries,etc.


Cell is Clearly Circulating

C-Cortical branches

C-Central branches

C-Choroidal branches

Sources: BD Chaurasia’s Human anatomy 7th edition-volume 4 -Circle of Willis by Luiz Roberto Meier Update 2


Getting or having braces is quite a big deal for sure with the long treatment period, follow-ups & the discomfort faced during and after adjustments made which includes dull soarness or throbbing pain along with some amount of restrictions on munching your favorite food during this period. 😦

But the end result of all this is an improved facial appearance with properly aligned teeth aiding in speech & mastication ; in short A healthy new smile :).

Is that the end of the story ?? Certainly not !!

The main part of the whole treatment is how you maintain the corrections made & retain it for future.

Here’s where terms like retention & relapse come into picture.

What is retention?

Maintaining newly moved teeth in position,long enough to aid in stabilizing their correction.-Moyers

Why do patients need retention?

Because of the post treatment changes that occur leading to relapse.

Relapse-Loss of any correction achieved by orthodontic treatment. Causes of relapse:

  • Periodontal ligment traction
  • Due to growth related changes
  • Bone adaptation
  • Muscular forces
  • Failure to eliminate the cause of malocclussion
  • Eruption of third molars
  • Role of occlusion

Schools of retention:

Theories of retention:

Riedel summarized the nine theories and Moyers added another theory which is the tenth theory mentioned here.

  • Theorem 1: Teeth that have been moved tend to return to their former position
  • Theorem 2:Elimination of the cause of malocclussion will prevent relapse
  • Theorem 3:Malocclussion should be over-corrected as a safety factor
  • Theorem 4: Proper occlusion is a potent factor in holding teeth in their corrected positions
  • Theorem 5:Bone & adjacent tissues must be allowed time to reorganize around newly positioned teeth
  • Theorem 6: If the lower incisors are placed upright over basal bone they are more likely to remain in good alignment
  • Theorem 7: Corrections carried out during the periods of growth are less likely to relapse
  • Theorem 8: The farther the teeth have been moved ,the lesser is the risk of relapse
  • Theorem 9: Arch form,particularly in the mandibular arch,cannot be permanently altered by appliance therapy
  • Theorem 10: Many treated malocclussion require permanent retaining devices

Remember as : REOP TLP FAR (REOPening To Let Patients Follow And Retain)


Sources: Bhalaji -Orthodontics the art and science,,


Many lesions that occur on the jaw present with similar radiographic appearances making it difficult to differentiate among them . Despite development of various cross sectional imaging modalities ,the radiographs are still remain the first and most important investigations.

So some of the common features that we as dentist might come across are listed below.I believe this would come handy for your radiodiagnosis😊.

  • Ghost teeth appearance-regional odontodysplasia
  • Ground glass appearance-monostotic fibrous dysplasia, hyperparathyroidism, middle stage of paget’s disease & ossifying fibroma,sickle cell anemia
  • Garrington sign-osteosarcoma (localised symmetrical widening of PDL
  • Hanging drop appearance-orbital blow out fracture
  • Heart shaped radiolucency-nasopalatine /incisive canal cyst
  • Honey comb appearance-anerysmal bone cyst,odontogenic myeloma,central giant cell granuloma,central hemangioma
  • Lincoln sign-paget’s disease (increased uptake in the mandible mimicking Lincoln’s beard.
  • Mass of color/ cauliflower like appearance-calcified lymph nodes
  • Moth eaten appearance-chronic osteomyelitis, early stage of ostesarcoma,radiolucent stage of fibrous dysplasia,squamous cell carcinoma,leukemia,malignant lymphoma
  • Mottled appearance-ossifying fibroma,fibrous dysplasia
  • Onion peel /skin appearance-Garre’s osteomyelitis, Ewing’s sarcoma,eosinophilic granuloma,caffey’s disease.
  • Orange peel appearance-mixed stage of fibrous dysplasia (peud-de-orange)
  • Pear shaped appearance-globulomaxillary cyst
  • Pepper pot appearance-hyperparathyroidism
  • Peripheral cuffing of bone-peripheral giant cell granuloma
  • Pressure type appearance-squamous cell carcinoma of gingiva
  • Punched out appearance-multiple myeloma
  • Rootless teeth appearance-dentinal dysplasia
  • Salt and pepper appearance-hyperparathyroidism, thalassaemia
  • Sausage like appearance-sialographic appearance of sialodochitis
  • Sialectasis-sialographic appearance of sialadenitis
  • Sharpened pencil appearance-osteoarthritis /rheumatoid arthritis of TMJ
  • Shell teeth appearance-type III dentinogenesis imperfecta
  • Soap bubble appearance-ameloblastoma,aneurysmal bone cyst,central hemangioma,central giant cell granuloma, odontogrnic keratocyst
  • Step ladder appearance-sickle cell anemia
  • Sunburst/sunray appearance-central hemangioma,osteosarcoma,Ewing’s sarcoma
  • Target sign-(rounded radiopacity with a central radiolucency)-impacted tooth in bucco lingual direction(lower 3rd molar)
  • Tennis racket appearance-odontogenic myxoma
  • Thistle tube appearance-type II dentinal dysplasia
  • Thumb print /fingerprint appearance-mixed stage of fibrous dysplasia
  • Tram track sign/calcifications-Sturge Weber syndrome
  • Trap door appearance-orbital blow out fracture
  • Tree in winter appearance-normal sialographic appearance of parotid gland

Some of the radiographic features are pathogonomic to a specific disease, thus can be helpful in narrowing down of differential diagnosis.

🖋Manisha M.A

Sources:White and Pharoah’s -Oral radiology textbook,Shafer’s textbook of oral pathology (8th edition) ,, Article-Phore S,Panchal RS,Bhagla P, Nabi N.Dental radiographic signs.Indian j health sci 2015;8:85-90.


The real importance of learning radiographic signs associated with specific disease is of relevance to clinical examination of the head & neck ; at the same time aiding in differentiating – what is normal from abnormal & hence appropriate treatment can be instituted for such conditions /abnormalities.

Here are the list of few radiographic appearances .

Cotton wool appearance seen on the lateral skull in Paget’s disease
  • Antral halo appearance-acute sinusitis
  • Ball in hand appearance-sialographic appearance of intrinsic benign tumor
  • Balloon like appearance-follicular cyst
  • Beaten silver/Copper beaten appearance-Crouzen syndrome,hypophosphatasia,craniofacial dysostosis ,obstructive hydrocephalus
  • Bush in winter appearance-normal sialographic appearance of submandibular gland
  • Candlestick appearance-Progressive systemic sclerosis,pycnodysostosis
  • Cherry blossom/branchless fruit laden tree/snowstorm/punctate sialectasis-sialographic appearance of Sjogren’s syndrome
  • Codman’s triangle-osteogenic sarcoma,Ewing sarcoma,carcinoma of alveolar ridge
  • Cotton wool appearance-paget’s disease,fibrous dysplasia(thick,amorphous radiopaque stage),cemmento-osseous dysplasia,chronic diffuse sclerosis osteomyelitis
  • Crew cut/Hair-on-end appearance-sickle cell anemia,thalassemia
  • Driven snow appearance-calcifying epithelial odontogenic tumor /cyst(Pindborg tumor)
  • Downward bowing appearance-cemento-osseous fibroma,ameloblastoma
  • Ely’s cyst-osteoarthritis
  • Filling defect appearance-salivary gland tumor
  • Floating tooth appearance-squamous cell carcinoma,malignant lymphoma,periodontitis ,eosinophilic granuloma,osteomyelitis

🖋Manisha M.A

Sources:White and Pharoah’s -Oral radiology textbook,Shafer’s textbook of oral pathology (8th edition),,Article-Phore S,Panchal RS,Bhagla P, Nabi N.Dental radiographic signs.Indian j health sci 2015;8:85-90.


  • Kocher’s sign-thyrotoxicosis
  • Macewen’s sign- alcohol poisoning
  • Murphy’s sign-acute cholecystitis
  • Nicolsky’s sign-application of pressure on normal skin produces a new lesion.Seen in pemphigus,TEN,Stevens Johnson syndrome ,Staphylococcla scalded syndrome
  • Osler’s sign- alkaptonuria
  • Pastia sign-scarlet fever
  • Pelken’s sign- scurvy
  • Prayer sign- diabetes
  • Raccoon eye sign-fracture of base of skull
  • Schamroth’s sign-clubbing
  • Signet ring sign-xray of patient with scurvy
  • Spatula sign-tetanus
  • Steinberg sign-Marfan’s syndrome
  • Tear drop sign- orbital blowout fracture
  • Trail sign- tracheal displacement
  • Tram track sign- Struge Weber syndrome
  • Trousseaus sign-seen in tetany
  • Trumbling bullet sign- post traumatic bone cyst
  • Water lily sign-hydatid cyst
  • Wimberger’s sign-congenital syphilis,scurvy
  • Wrist sign-Marfan’s syndrome in medicine),


  • Allis sign- seen in developmental dysplasia
  • Asboe sign- seen in pemphigus (Bulla spread sign)
  • Auspitz sign- seen in psoriasis -peeling away scales result in pin point bleeding spots
  • Albright sign -dimple at the metacarpelopharyngeal joint, due to short metacarpal.Seen in pseudohypoparathyroidism,Turner’s syndrome,basal cell carcinoma
  • Babinski’s sign- by stroking the lateral aspect of the dorsum of foot
  • Barber’s chair sign- seen in multiple sclerosis
  • Battle’s sign-in basal skull fracture(sphenoid bone)blood pigment stain behind the ear over the mastoid
  • Benda’s sign- in tuberculous meningitis.Spasm of the trapezius muscle that the shoulder on affected side is lifted and at times brought forward
  • Blue berry muffin sign-raised purple lesions seen in dermal metastases of neuroblastoma
  • Brim sign- seen in Paget’s disease
  • Brudzinski’s sign- seen in meningitis
  • Button hole sign- seen in neurofibromatosis
  • Carpet track sign- seen in discoid lupus erythematosis
  • Cerebriform tongue sign- seen in pemphigus veterans
  • Chandelier’s sign- seen in gonorrhea in women
  • Chvostek sign- elevation of corner of mouth
  • Coleman’s sign- in fracture of body of mandible ( hematoma seen in the floor of the mouth)
  • Corner’s sign- seen in scurvy
  • Crowe’s sign- seen in neurofibromatosis
  • Darier sign- seen in urticaria pigmentosa
  • Dubois sign- seen in congenital syphilis
  • Erb’s sign- seen in latent tetany
  • Paget’s sign- seen in yellow fever
  • Falling fragment sign- seen in solitary bone cyst
  • Fitzpatrick sign- seen in dermatofibroma
  • Flag sign- seen in kwashiorkor
  • Floating membrane sign-seen in hydatid cyst
  • Floating teeth sign- seen in eosinophilic granuloma
  • Forscheimer sign- seen in rubella
  • Head drop sign- seen in poliomyelitis
  • Heel pad sign- seen in acromegaly
  • Higoumanaki’s sign- seen in late syphilis
  • Hutchinson sign-seen in heroes zoster ophthalmicus
  • Jellinek sign-seen in hyperthyroidism
  • Joffroy’s sign-seen in thyrotoxicosis

Source: ( signs in medicine),


Pigmentation is the process of deposition of pigments in the tissue.Mostly found in the mouth and could be attributed to oral manifestations of systemic diseases or malignancies.This could be due to :

  • Increased number of melanocytes
  • Augmentation of melanin production
  • Deposition of accidentally introduced exogenous materials

The various oral pigmentations can be in the form of:

1)Blue /Purple vascular lesions-

  • Hemangioma
  • Varix
  • Angiosarcoma
  • Kaposi’s sarcoma
  • Hereditary hemorrhagic telangiectasia

2)Brown melanotic lesions-

  • Ephelis & oral melanotic macule
  • Nevus
  • Malignant melanoma
  • Drug induced melanosis
  • Physiologic pigmentation
  • Cafè au lait pigmentation
  • Smoker’s melanosis
  • Endocrinopathic pigmentation
  • Peutz-jeghers syndrome
  • HIV oral melanosis

3)Brown heme associated lesions-

  • Ecchymosis
  • Petechia
  • Hemochromatosis
  • Hemorrhagic mucocele
  • Thrombosed varix

4)Gray/black pigmentations-

  • Silver amalgam tattoo
  • Graphite tattoo
  • Heavy metal ingestion-lead,mercury,bismuth
  • Hairy tongue


Appearance of peculiar spots in specific sites on the body are often diagnostic for major systemic disease or condition or an infection.Some of them are discussed here;

  • Koplik spots -measles (rubeola)
  • Pink spots on teeth – internal resorption
  • Roth spots – subacute endocarditis, typhoid fever
  • Bitot’s spots white plaque on conjunctiva of vitamin A deficient children
  • Herald spots -primary lesion seen in pitryiasis rosea
  • Sore spots -traumatic ulcers from denture irritation mostly
  • Cafè au lait spot-neurofibromatosis, Macune-Albright syndrome,Peutz-jeghers syndrome

Sources: Shafers textbook of oral pathology , (oral pigmentation : A review),


Cigarettes contain nicotine and by smoking regularly and for long hours, your body becomes dependent on it. Giving up smoking can cause nicotine withdrawal symptoms which are :

  • Restlessness ,impatience
  • Eating more than usual
  • Anxiety / tension
  • Headaches,irritability / anger
  • Difficulty in concentration + Depression
  • Loss of energy,dizziness
  • Sweating
  • Insomnia
  • Stomach or bowel problems
  • Heart palpitations
  • Tremors
  • Craving for tobacco

Stop smoking medicines along with nicotine replacement therapy are effective aid to tobacco cessation & can help control these symptoms.

What are these?

3 types –

  • Champix tablets (varenicline)
  • Zyban tablets (bupropion)
  • Nicotine replacement therapies (gums,patches,lozenges,microtabs,sublingual tablets,insulators,cigs,nasal sprays)

How does it work?

Tobacco intakers who are motivated to quit the habit & are dependent on nicotine should be offered NRT.

  • Prescribed for 6 to 8 weeks,in blocks of up to 2 weeks,contingent on continued abstinence.
  • If one type of NRT is not working for the patient ,the health professional is advised to prescribe a suitable type informing about the dosage & maximum amount to take a day.

Is it safe?

NRT is safe because of the facts that the nicotine levels are low and it’s less addictive delivery mechanism (unlike smoking tobacco where the nicotine reaches the brain quickly) and also because most of the harmful problems are caused by the other components of tobacco smoke ,not by the nicotine.

NRT is safe for most adults and in people with stable cardiac diseases, but caution needed in unstable,acute cardiovascular disease,pregnancy,or breastfeeding or in those aged under 18 years.

Brownie points-reduces the constant urge to munch on food,thus reducing weight gain.😊

When should one stop using NRT?

Most courses of NRT recommend use for about 12 weeks.This is because it takes this much time for the brain to adjust to working without the high doses of nicotine that the cigarettes supply.However there is no hard and fast rule.After starting the therapy,most people mistake the lack of discomfort for the belief that the addiction is over,leading to stop using the product too soon. This can result only in reappearing of the symptoms.

The best method is to take the help of the health professional when you start the therapy and keep them updated about the progress.

Lastly ,we all are not the same….each tobacco smoker’s tendency & pattern to quit may vary & it depends on different factors like age,gender,environment, general physical and mental health.

Sources:S.S Hiremath textbook of preventive and community dentistry, Support)


Tobacco is the leading preventable cause of death in the world and is the only consumer product that kills when used as intended by its manufacturers ;which may become deadly for non-smokers also.


  • Tobacco causes 1 in 10 adult deaths worldwide,nearly 5 million deaths a year or one death every 6.5 seconds,killing 50% of regular users.
  • Total global smoking prevalence is 29%;47.5% men & 10.3% women.
  • By 2030,70% of deaths in the world is attributable to tobacco.
  • It’s a known or probable cause of about 25 diseases.
  • Smokeless tobacco causes oral cancer,especially in lips,tongue,mouth and throat area.
  • Breathing Environmental Tobacco Smoke(ETS) (i.e .side stream,exhaled smoke from cigarettes,cigars and pipes)causes serious health problems & aggravates allergies and increase the severity of symptoms in children & adolescents, with asthma and heart diseases.
  • People who start using tobacco early have more difficulty in quitting,are more likely to be heavy smokers and if young people donot begin to use tobacco before the age of 20,they are unlikely to start the habit.
  • The World Bank estimated that smoking prevention is among the most effective of all health interventions.
Deadlier than ever-how cigarettes have evolved over last 50 years.


  • Electroencephalographic desynchronisation.
  • Increased circulating levels of catecholamines, vasopressin, growth hormone,adenocorticotropic hormone,cortisol,prolactin,and beta-endorphin.
  • Increased metabolic rate
  • Lipolysis,increased free fatty acids.
  • Heart rate acceleration, nicotine can increase the heart rate by 10-15 beats/min.
  • Cutaneous & coronary vasoconstriction
  • Increased cardiac output & blood pressure by 5-10 mm Hg
  • Skeletal muscle relaxation
  • Nicotine can induce pathogenic changes to the endothelium associated with atherosclerotic process.
  • Halitosis,staining of teeth and soft tissues(smokers melanosis),drying of mouth.

‘Nicotine itself is not carcinogenic unless it undergoes nitrosation to form nitrosamines(during tobacco curing & combustion).’


A question-answer session with the individual would be very helpful ….

The total score can be calculated to know the dependence.

THE 5 A’S :

  • ASK- health care professionals / dentists should ask the patient about his or her tobacco intake habits which includes the questions discussed above,during every visit.
  • ADVICE-health care professional / dentists should continually advice patient to quit the habit thereby emphasizing the importance of the issue.
  • ASSESS- patients readiness & motivation to quit the habit must be assessed- cause this is a ‘major lifestyle change & requires preparation, readiness & several failed attempts’.
  • ASSIST-health care professionals/ dentists should assist those individuals who are motivated- by informing,suggesting and prescribing a pharmacological cessation aids ( nicotine replacement therapy ) and providing or referring the patient to counseling ( individual, group or over telephone ) and behavioral therapies and support services where available.
  • Lastly,ARRANGE-follow up services are often critical & the dentists can help the patient be tobacco free by providing services like advising availability of national hotlines,support from non-smoking friends or colleagues,or community based support groups.
The best time to quit smoking was the day you started,the second best time is today.

Lastly ,dentists play a major role in helping a patient quit smoking because we might be the first to detect an abnormality( be it a small stain or an abnormal mass ) in the oral cavity during routine examination. Do your part ,every small step counts……

Sources- S.S Hiremath textbook of preventive and community dentistry , ,


Correct and early diagnosis of a lesion / abnormality in the oral cavity is very crucial as these could be vital indicators to some of the underlying systemic diseases or other chronic conditions. Most of the oral conditions show a peculiar pattern of occurrence only on specific sites.Hence,knowledge of these common sites can help to some extent in proper identification, differentiation from other similar conditions and treatment planning.A few of such conditions and findings has been mentioned here.

Sources:Shafers textbook of oral pathology ,burkets oral medicine ,