Bleaching is a procedure which involves the lightening of the color of the tooth through the application of a chemical agent to oxidize the organic pigmentation of the tooth.
Properties of an ideal bleaching agent
An ideal bleaching agent should:
be easy to apply on the teeth
have a neutral pH
lighten the teeth efficiently
remain in contact with oral soft tissues for short periods
be required in minimum quantity to achieve desired results
not irritate or dehydrate the oral tissues
not cause damage to the teeth
be well controlled by the dentist to customize the treatment of patient needs.
Bleaching Techniques:
a) For Vital Teeth
- Home bleaching technique / Night guard vital bleaching / Matrix bleaching
# Macrolide antibiotics are usually avoided in asthmatics because:
A. it can precipitate asthmatic attack
B. it interacts with theophylline
C. such patients are usually allergic to penicillins
D. such patients show penicillin resistant infections
# Anticoagulation therapy should be advised to discontinue before minor or major oral surgical procedures if:
A. INR (international normalized ratio) is less than 3.0
B. INR is more than 3.0
C. PT (Prothrombin time) is less than 10 seconds
D. PT is in range of 10-15 seconds
# Which of the following oral manifestations can be often seen in asthmatics?
A. Xerostomia
B. Geographic tongue
C. Enamel hypoplasia
D. Aphthous ulcers
# A male patient of 76 yrs is on warfarin therapy and needs emergency extractions of a decayed tooth. Select the appropriate protocol given below.
A. Do not stop the warfarin therapy – perform the surgery with local hemostatic agents - administer vitamin K if necessary.
B. Administer heparin along with warfarin – perform the surgery
C. Advise INR – If INR is less than 2 perform surgery, if more than 2 do not perform the surgery
D. Extraction cannot be done to a patient who is on warfarin therapy
# A hospitalized patient on heparin therapy needs dental extraction. Select the antidote for such patients from the following:
A. Warfarin
B. Desmopressin acetate (DDAVP)
C. Vitamin K
D. Protamine sulfate
# Endocarditis prophylaxis is recommended in one of the following conditions before extractions:
A. Cardiac pacemakers
B. Mitral valve prolapse without valvular regurgitation
C. Tetralogy of Fallot
D. Implanted defibrillators
# Which of the oral procedures will not need any antibiotic prophylaxis to minimize the risk of bacterial endocarditis?
A. Root planing
B. Suture removal
C. Placement of orthodontic bands
D. Intraligamentary injections
# Why erythromycin and tetracyclines are prescribed carefully in patients with peptic ulcers?
A. Increases acid production
B. Interacts with acid and the drug availability is reduced
C. Interacts with antacids if any
D. Both are bacteriostatic
# Pigmentation of the face, lips and oral cavity is seen in a patient who gives a history of intestinal polyps. The systemic disorder that is present is:
A. Peutz Jeghers syndrome
B. Cowden's syndrome
C. Gardner's syndrome
D. Addison's disease
# Prilocaine, an amide type of local anesthetic should not be used in one of the following conditions:
A. Renal disorders
B. Hypotension
C. G6PD deficiency
D. CNS disorders
# Choose one of the following medications that can be safely administered to a patient with chronic renal failure without any change in dosages.
A. Doxycycline
B. Gentamicin
C. Amoxicillin
D. Ciprofloxacin
# 'Mona Lisa face' is seen in which disorder?
A. Angioedema
B. Scleroderma
C. Discoid lupus erythematosus
D. Sjogren syndrome
# Which of the following are the prominent features of Behcet's disease?
A. Aphthous stomatitis, anemia, cardiac arrhythmia
B. Genital ulcers, dermal pustules, oral ulcers
C. Hematuria, periodontitis, xerostomia
D. Arthralgia, geographic tongue, ear infections
# Facial xanthomas may help in recognition of:
A. Porphyria
B. Waldenstrom's hypergammaglobulinemia
C. Hyperlipoproteinemia
D. Homocysteinuria
# One of the following disorders will not cause scarring of oral mucosa:
A. Major aphthae
B. Erythema multiforme
C. Epidermolysis bullosa dystrophica
D.
# In a patient with cardiac pacemaker, which of the following equipment can be safely used?
A. MRI
B. Ultrasonic scaler
C. Electrocautery
D. Radiographic equipment
# In a 58 year old female with insulin dependent diabetes mellitus under treatment, surgical removal of impacted mandibular third molar can be performed only if the glycated hemoglobin value is:
A. less than 80 %
B. less than 88 %
C. less than 8 %
D. less than 18 %
# A patient gives history of viral hepatitis C after undergoing liver transplant. He is on immunosupressive medications. On examinations of oral cavity, white striated lesions were present. It could be any of the following EXCEPT:
A. Graft vs host disease
B. Oral lichen planus
C. Lichenoid reaction
D. Leukoplakia
# A patient who is on high doses of corticosteroid therapy will face all of the following problems during dental treatments except:
A. Impaired wound healing
B. minor difficulties to achieve hemostasis
C. Xerostomia
D. susceptibility to infections
# What crystals are deposited in TMJ in gouty arthritis?
A. Monosodium urate
B. Calcium hydroxyapatite
C. Calcium pyrophosphate dihydrate
D. Calcium dihydroxide
# An elderly patient under corticosteroid therapy has to undergo dental extraction. Which is the best method to proceed?
A. Taper the dose and perform the extraction
B. Completely stop the drug and then perform the extraction
C. Supplementation of corticosteroids should be given before extraction
D. Stop the drugs immediately after extraction to allow healing
# A patient presents with bilateral facial palsy and uveitis with enlargement of parotid glands. He could be suffering from:
A. Ramsay Hunt syndrome
B. Melkerson Rosenthal Syndrome
C. Heerfordt syndrome
D. Sjogren syndrome
# A 67 year old male with a medical history of bronchial asthma and glaucoma was diagnosed of xerostomia. The appropriate method to manage the condition is:
A. Pilocarpine 5 mg thrice daily
B. Cevimeline HCl 10mg twice to thrice daily
C. Anetholetrithione
D. Artificial saliva
# 'Crowe sign' is seen in which of the following diseases?
A. Neurofibromatosis I
B. Albright syndrome
C. MEN type III
D. Cowden syndrome
# 'Coast of Maine' like border is seen in pigmented lesions of:
A. Von Recklinghausen's disease
B. Peutz - Jeghers syndrome
C. McCune Albright syndrome
D. Acanthosis nigricans
# Pseudomembranous candidiasis is seen in oral cavity of AIDS patients commonly when CD4 cells count:
A. less than 80 cells per cubic mm
B. less than 400 cells per cubic mm
C. less than 1000 cells per cubic mm
D. less than 4000 cells per cubic mm
# Trigeminal neuralgia, sensory neuropathy of trigeminal nerve and facial palsy can be usually seen in which of the following diseases?
A. Parkinsonism
B. Amyotrophic lateral sclerosis
C. Multiple sclerosis
D. Alzheimer's disease
# Macroglossia is seen in all of the following systemic diseases except:
A. Cretinism
B. Amyloidosis
C. Beckwith's hypoglycemic syndrome
D. Oral facial digital syndrome
# 'Rh hump' is the term used to describe:
A. hump back seen in Rh negative people
B. green or blue hue seen in teeth of erythroblastosis fetalis
C. ring-like enamel hypoplasia seen in erythroblastosis fetalis
D. hump joints seen in rheumatoid arthritis
# Chromosomal studies should be performed in a patient with taurodontism, mental retardation, tall and thin appearance with prognathic jaws to detect which of the following disorders ?
A. Rubinstein Taybi Syndrome
B. Klinefelter syndrome
C. Acromegaly
D. Osteogenesis imperfecta
# Saddle nose is seen in all of the following disorders except:
A. Osteogenesis imperfecta
B. Thalassemia major – β
C. Congenital syphilis
D. Crouzon syndrome
# “Crocodile tears” is seen in:
A. Horton‟s syndrome
B. Frey‟s syndrome
C. Raeder‟s syndrome
D. Meniere‟s disease
# Widespread osteosclerosis is present in all of the following diseases except:
A. Marble bone disease
B. Paget‟s disease
C. Generalized cortical hyperostosis
D. Phantom bone disease
# “Bald tongue of Sandwith” is an oral manifestation of:
A. Pellagra
B. Pernicious anemia
C. Iron deficiency anemia
D. Fanconi‟s anemia
# “Tapir lips” (patient unable to whisper or smile- myopathic facies) is seen in:
A. Bell‟s palsy
B. Marcus Gunn phenomenon
C. Muscular dystrophy
D. Myasthenia Gravis
# A patient with Down‟s syndrome should be sent for Physician opinion before doing any extraction. Choose the appropriate justification.
A. As they are mentally retarded, physician opinion is sought.
B. They will have to undergo multiple extractions, hence opinion is obtained.
C. Down‟s syndrome is usually associated with cardiac problems which may need antibiotic prophylaxis.
D. Local anesthesia may cause anaphylactic reactions in such patients.
# Which among the following antibiotics commonly used in dentistry may not cause pseudomembranous colitis?
A. Erythromycin
B. Ampicillin
C. Clindamycin
D. Metronidazole
# Oral bacteremias after a tooth extraction are:
A. now considered as a myth
B. generally transient & last for less than one hour
C. present at least for 6 hours
D. rare with Streptococci Viridans
# In a patient with splenectomy, which of the following is not a matter of concern for a dentist?
A. Antimicrobial prophylaxis
B. Thrombocytopenia
C. Corticosteroid therapy
D. Bleeding dyscrasias
World Oral Health Day 2018 was celebrated by multiple events like poster and flex competition, Speech competition and Table Clinic Competition. College of Dental Surgery, BPKIHS in coordination with Nepal Dental Association, Sunsari, organized the program. Also, 4th year BDS students as a part of their social responsibility for public awareness acted out a play regarding health hazards of drinking, smoking and chewing areca nut. The winners of Poster competition were Shabnam Gurung and Pratima Rai of BDS 2014 batch and the winner of Table Clinic Presentation were Anumesh Dahal and Nitika Santhaliya.
2017
1. Describe briefly the kinetics and life span of leucocytes. Compare and contrast the functions of neutrophils and eosinophils. 2+3=5
2. Describe the sequence of reactions to mismatched blood transfusion. 5
3. Explain the genesis of granulocytes and their regulation using flow chart. 5
4. Explain the anticoagulant mechanisms of endothelium of blood vessel. 5
5. Describe the role of platelets in hemostasis. 5
2016
1. Enlist the functions of plasma proteins. Explain any one of them. 2.5+2.5=5
2. What is cross matching in blood transfusion? Explain its significance. 3+2=5
3. Define hemostasis and describe about any 3 anti-clotting mechanisms in the body 2+3=5
4. Explain the different stages of erythropoiesis with a diagram. 5
5. Differentiate between intrinsic and extrinsic pathways of blood coagulation. 5
2015
1. What is Rh factor? Explain the consequence of Rh incompatibility in blood transfusion and pregnancy. 1+5=6
2. Describe the role of endothelium blood vessels in anticlotting mechanism. 4
3. Describe the cytoskeletal proteins of RBC. List 4 advantages of biconcavity of RBC. 3+2=5
4. Draw a flow-chart showing stages of erythropoiesis. State the role of erythropoietin on it. 3+2=5
5. Enlist five functions of plasma proteins. Explain any one of them. 3+2=5
2014
1. State any four factors regulating erythropoiesis. Explain the most important factor among them. 2+3=5
2. Enlist any five functions of plasma proteins. Describe any one of them. 2.5+2.5=5
3. What is cross matching in blood transfusion? Explain its significance. 3+2=5
4. Explain the intrinsic pathway of blood coagulation with the help of a flow diagram. 5
5. Explain the role of thrombomodulin and plasminogen in anti-clotting mechanism 2.5+2.5=5
2013
1. Explain the mechanism of clot dissolution. 5
2. Mention any four mechanisms that normally prevent coagulation of blood inside the blood vessels. Describe any one them. 2+3=5
3. Describe the regulatory role of erythropoietin in red blood cells production. 4
4. State Landsteiner’s law of blood grouping with examples. 3+2=5
5. Mention any four functions of plasma proteins. Describe
any two of them. 2+2+2=6
2012
1. Describe various stages of erythropoiesis with changes that occur during each successive stage. 4+2=6
2. Briefly describe the fate of hemoglobin breakdown. 5
3. Describe briefly the mechanism of platelet plug formation. 4
4. Explain in brief the anti-fibrinolytic mechanisms. 5
5. Briefly describe Rh incompatibility. 5
2011
1. Define cytokines. Explain their role in hemopoiesis with flowchart. 1+4=5
2. Explain the role of endothelium of blood vessels inn anti- clotting mechanism. 5
3. How circulatory neutrophils invade the offending agents in an area of tissue damage & perform the bactericidal effect? 3+2=5
4. Describe the consequences of mismatched blood transfusion. 5
5. Explain the role of erythropoietin in the erythropoiesis. 5
2010
1. List the major contents of platelets and briefly function. 5
The American Society for Testing and Materials (specification D 907) defines adhesion as “the state in which two surfaces are held together by interfacial forces which may consist of valence forces or interlocking forces or both.” (ref. 2)
In dentistry, bonding of resin-based materials to tooth structure is a result of four possible mechanisms, as follows: (ref. 3)
Mechanical
Adsorption
Diffusion
Combination of above three
For good adhesion, close contact must exist between the adhesive and the substrate (enamel or dentin). The surface tension of the adhesive must be lower than the surface energy of the substrate.
ENAMEL
Acid-etching transforms the smooth enamel into an irregular surface and increases its surface free energy. When a fluid resin-based material is applied to the irregular etched surface, the resin penetrates into the surface, aided by capillary action. Monomers in the material polymerize, and the material becomes interlocked with the enamel surface. (ref 4,5) The formation of resin microtags within the enamel surface is the fundamental mechanism of resin-enamel adhesion. (ref. 6,7)
Scanning electron micrograph (SEM) of enamel etched with 35 % phosphoric acid for 15 seconds
DENTIN
Adhesive materials can interact with dentin in different ways—mechanically, chemically, or both. The importance of micromechanical bonding, similar to what occurs in enamel bonding, has become accepted. (ref. 8) Dentin adhesion relies primarily on the penetration of adhesive monomers into the network of collagen fibers left exposed by acid etching. (ref. 9,10) However, for adhesive materials that do not require etching, such as glass ionomer cements and some phosphate-based self-etch adhesives, chemical bonding between polycarboxylic or phosphate monomers and hydroxyapatite has been shown to be an important part of the bonding mechanism. (ref. 11)
Higher magnification view of dentin etched with 35 % phosphoric acid, col- collagen exposed by the acid, D- normal dentin, T - dentinal tubule, S- residual silica particles used as acid gel thickener
CEMENTUM
Cementum is the first target for plaque bacteria attack in the process of root caries formation, and is still thought to be the most unpredictable area of an adhesive resin restoration. Cementum hybridization is related to structure, chemical composition and bonding efficacy of human cementum, which has a lower packing density than dentin. Cementum is a specialized and mineralized tissue (20–200 micrometers thick), pale yellow with dull surface. The principal inorganic component is hydroxyapatite while other forms of calcium are also present. It is considered to be rich in organic phase (about 50%) of collagen fibers and other matrix proteins. The ultrastructure of etched cementum surfaces was of a more spongy appearance with a large collagen fiber network compared with that of dentin, displaying longer and more deeply voluminous array of tufted fibrils. It is less hard and more permeable to a variety of materials compared with enamel and dentin.
Cementum in the cervical area is an acellular extrinsic fiber cementum. This substratum is a nonuniform, and relatively rough tissue. Human cementum can be represented as a woven fabric-like material that provides tissue porosity and permeability. One of the surface features that distinguish demineralized cementum from dentin is a lack of patent tubule orifices. With an absence of these openings, cementum is at a distinct disadvantage when it comes to enhanced bonding adhesion.
AFM (Atomic force microscopy) images of 50 micrometer * 50 micrometer area of 35% H3PO4 etched cementum
References:
1. Sturdevant's Art and Science of Operative Dentistry, 6th Edition
2. Packham DE: Adhesion. In Packham DE, editor: Handbook of adhesion, Essex, UK, 1992, Longman Scientific & Technical, pp 18–20.
3. Söderholm K-JM: Correlation of in vivo and in vitro performance of adhesive restorative materials: A report of the ASC MD156 Task Group on test methods for the adhesion of restorative materials. Dent Mater 7:74–83, 1991.
4. Asmussen E, Munksgaard EC: Bonding of restorative materials to dentine: Status of dentine adhesives and impact on cavity design and filling techniques. Int Dent J 38:97–104, 1988.
5. Buonocore MG, Matsui A, Gwinnett AJ, et al: Penetration of resin into enamel surfaces with reference to bonding. Arch Oral Biol 13:61–70, 1968.
6. Barkmeier WW, Shaffer SE, Gwinnett AJ, et al: Effects of 15 vs 60 second enamel acid conditioning on adhesion and morphology. Oper Dent 11:111–116, 1986.
7. Gwinnett AJ, Matsui A: A study of enamel adhesives: The physical relationship between enamel and adhesive. Arch Oral Biol 12:1615–1620, 1967.
8. Erickson RL: Surface interactions of dentin adhesive materials, Oper Dent 5(Suppl):81–94, 1992.
9. Van Meerbeek B, Ionkoshi S, Braem M, et al: Morphological aspects of the resin-dentin interdiffusion zone with different dentin adhesive systems. J Dent Res 71:1530–1540, 1992.
10. Tay FR, Gwinnett AJ, Wei SH, et al: Ultrastructure of the resin-dentin interface following reversible and irreversible rewetting. Am J Dent 10:77–82, 1997. 11. M. Toledano, E. Osorio, F.S. Aguilera, G. Gomes, J. Perdigão, R. Osorio, Bond strength and nanoroughness assessment on human pretreated cementum surfaces, Journal of Dentistry, Volume 38, Issue 8, 2010, Pages 678-685, ISSN 0300-5712, https://doi.org/10.1016/j.jdent.2010.05.011. (http://www.sciencedirect.com/science/article/pii/S030057121000120X) Keywords: Adhesion; Dental; Cementum; Phosphoric acid; Etching; Self-etching; Adhesives; Nanoroughness; Surface; AFM
