৪৮তম বিশেষ বিসিএস [স্বাস্থ্য] ⎯ ডেন্টাল অংশ [Archived]

Internal resorption occurs due to activated odontoclasts in vital pulp; apical pulp may be inflamed but vital.

Internal resorption is the progressive destruction of the intraradicular dentin and pulp chamber walls due to clastic activity, usually triggered by chronic inflammation or trauma inside the pulp.

Key points:
- It occurs within the root canal system.
- Clinically, it’s often asymptomatic and discovered on radiographs as a radiolucent, round or oval enlargement of the pulp space.
- Causes include trauma, caries, or pulpitis.
- Treatment involves root canal therapy to remove inflamed pulp tissue and stop resorption.

Reference:
The textbook of endodontics by Nisha Garg (Chapter: Internal Resorption)

Lingering pain after stimulus removal indicates irreversible pulpitis, necessitating endodontic treatment.

Cardinal features of irreversible pulpitis are:

- Severe spontaneous pain
- Prolonged lingering pain to thermal stimuli (especially cold or heat)
- Pain worsens on lying down or at night
- Pain may radiate to adjacent areas
- Sensitivity to percussion and palpation may be present
- Pulp tissue is inflamed beyond repair and cannot heal

Reference:
The textbook of endodontics by Nisha Garg (Chapter: Pulpal Pathology and Diagnosis)

Smear layer consists of both organic (tissue remnants, bacteria) and inorganic debris from instrumentation, not medicaments.
Reference: Garg & Garg, 2024

Laser Doppler flowmetry measures blood flow, providing an accurate assessment of pulp vitality.

Methods of pulp vitality test:

1. Thermal Tests
- Cold test (using refrigerants like ice, CO2)
- Heat test (heated gutta-percha or warm instruments)

2. Electric Pulp Test (EPT)
- Uses electrical stimulus to check pulp response

3. Test Cavity
- Invasive, used when other tests are inconclusive

4. Laser Doppler Flowmetry
- Measures blood flow in pulp (advanced technique)

5. Pulse Oximetry
- Non-invasive, measures oxygen saturation in pulp

Reference:
The textbook of endodontics by Nisha Garg

Sterilization techniques

1. Moist Heat Sterilization (Autoclave)
- Uses saturated steam under pressure (121°C for 15-20 mins)
- Most widely used and effective

2. Dry Heat Sterilization
- Hot air oven (160-170°C for 1-2 hours)
- Suitable for instruments that may corrode with moisture

3. Chemical Vapor Sterilization
- Uses formaldehyde and alcohol vapors under pressure
- Requires proper ventilation

4. Ethylene Oxide Sterilization
- Gas sterilization for heat-sensitive instruments
- Requires aeration time to remove toxic gas

5. Cold Chemical Sterilization
- Soaking instruments in chemical solutions like glutaraldehyde
- Used for instruments that cannot tolerate heat

Reference:
The textbook of endodontics by Nisha Garg (Chapter: Infection Control and Sterilization)

Sharps (needles, blades) must be discarded in rigid white containers to prevent injury.

Hedstrom files are the most aggressive cutters, while reamers are the least.

DG-16’s angled tips allow precise access and tactile feedback during canal orifice detection.

Access Cavity Outlines for Different Teeth
(The textbook of endodontics by Nisha Garg - Access Cavity Preparation)

- Maxillary Central Incisor: Triangular
- Maxillary Lateral Incisor: Triangular
- Maxillary Canine: Oval
- Maxillary First Premolar: Oval or Rounded Triangular
- Maxillary Second Premolar: Oval
- Maxillary First Molar: Rhomboid or Triangular
- Maxillary Second Molar: Rhomboid
- Mandibular Central Incisor: Triangular or Oval
- Mandibular Lateral Incisor: Triangular or Oval
- Mandibular Canine: Oval
- Mandibular First Premolar: Oval
- Mandibular Second Premolar: Oval
- Mandibular First Molar: Rectangular
- Mandibular Second Molar: Rectangular or Rhomboid

Mechanism of Action of Calcium Hydroxide
(The textbook of endodontics by Nisha Garg – Chapter: Root Canal Medicaments)

1. High Alkalinity (pH ~12.5):
- Creates an environment hostile to bacteria
- Denatures proteins and damages bacterial cytoplasmic membranes

2. Antibacterial Action:
- Hydroxyl ions disrupt bacterial enzymes and DNA

3. Tissue Dissolution:
- Promotes dissolution of necrotic tissue remnants

4. Induces Hard Tissue Formation:
- Stimulates alkaline phosphatase activity
- Promotes mineralization and dentin bridge formation

5. Neutralizes Endotoxins:
- Inactivates bacterial lipopolysaccharides (LPS)

Calcium hydroxide is widely used in apexogenesis, apexification, and as an intracanal medicament.

Factors Affecting Accuracy of Apex Locator
(The textbook of endodontics by Nisha Garg – Chapter: Working Length Determination)

1. Presence of Electrolytes
- Saliva, blood, irrigants (e.g., NaOCl) may influence readings

2. Canal Condition
- Dry or overly wet canals can alter accuracy

3. Open Apex
- Less reliable in immature teeth

4. Metallic Restorations or Crowns
- Can cause electrical interference

5. Proper File Contact
- File must contact canal walls and be snug

6. Device Calibration
- Proper use and battery condition matter

7. Root Resorption or Perforations
- May give false readings if apex anatomy is altered

8. Operator Technique
- Inaccurate placement or poor sealing can distort results

Step Back Technique
(The textbook of endodontics by Nisha Garg – Chapter: Biomechanical Preparation)

Definition:
A manual root canal preparation technique where the apical portion is prepared first, followed by sequential flaring of the canal toward the coronal portion using progressively larger files.

Steps:

1. Establish Working Length
2. Apical Enlargement
- Prepare apical third to master apical file (MAF), e.g., size 25 or 30
3. Step Back
- Use successively larger files (e.g., 35, 40, 45...)
- Each used 1 mm shorter than the previous one
4. Recapitulation
- Use small file to maintain patency and remove debris
5. Irrigation
- Frequent use of irrigants during instrumentation

Advantages:
- Good apical control
- Reduces debris compaction
- Creates tapered preparation

Disadvantages:
- Time-consuming
- Greater chance of procedural errors if not careful (ledging, transportation)

(The textbook of endodontics by Nisha Garg – Chapter: Procedural Accidents)

Common errors during endodontic treatment:

1. Access Cavity Errors
- Incomplete access
- Perforation of the pulp chamber floor or wall

2. Instrumentation Errors
- Ledge formation
- Zipping
- Canal transportation
- Apical perforation
- Instrument separation (file breakage)

3. Obturation Errors
- Underfilling
- Overfilling
- Voids in obturation
- Missed canals

4. Irrigation Errors
- Sodium hypochlorite accident (extrusion into periapical tissues)

5. Post-endodontic Errors
- Fracture of tooth due to delayed restoration
- Coronal leakage

Causes of Surgical Endodontic Failure:

1. Incomplete Root-End Resection
- Infected root tip not fully removed

2. Inadequate Root-End Filling
- Poor sealing of retrograde cavity
- Use of unsuitable materials

3. Missed Canals or Isthmus
- Failure to identify or clean anatomical variations

4. Residual Infection
- Persistent bacteria in periapical tissues or uncleaned canal space

5. Improper Flap Design or Closure
- Poor healing due to tension or infection at surgical site

6. Vertical Root Fracture
- Undiagnosed fracture leading to persistent symptoms

7. Systemic/Healing Factors
- Patient-related issues like diabetes, smoking, or poor immune response

Prevention Tips:
- Accurate diagnosis and case selection
- Use of magnification (microscope)
- Proper retrograde filling with biocompatible material (e.g., MTA)
- Aseptic technique during surgery

Careful technique and post-op follow-up improve surgical success rates.


Reference :(The textbook of endodontics by Nisha Garg – Chapter: Endodontic Surgery)

 Overfilling in primary molar pulpectomy can lead to:

Foreign body reaction (due to non-resorbable or irritating material) 
Interference with permanent tooth eruption, causing delayed or ectopic eruption.

Child Age Classification

1. Infancy: Birth to 1 year
2. Toddler: 1 to 3 years
3. Preschool: 3 to 5 years
4. School Age: 6 to 12 years
5. Adolescence: 13 to 18 years

From Principles and Practice of Pedodontics by Arathi Rao, here’s a detailed discussion on behavior management techniques used in pediatric dentistry:

Behavior Management Techniques

1. Communicative Management
- Tell-Show-Do (TSD):
- Tell: Explain the procedure in simple, non-threatening terms.
- Show: Demonstrate on a model or finger.
- Do: Perform the procedure as described.
- Highly effective and widely used.

- Voice Control:
- Modulating tone, volume, and pace to gain the child’s attention and compliance.
- Best for disruptive behavior; should be used ethically and with consent.

- Positive Reinforcement:
- Verbal praise, stickers, or small rewards for cooperative behavior.
- Encourages repetition of desired behavior.

- Distraction:
- Shifting the child's focus during treatment (e.g., storytelling, toys, videos).
- Helps reduce anxiety and improve cooperation.

- Non-verbal Communication:
- Using facial expressions, gestures, and eye contact to communicate encouragement or control.

2. Parental Involvement
- Presence/Absence Technique:
- Decisions about whether parents should be in the operatory are based on child’s age and behavior.
- Some children behave better without the parent present.

3. Aversive Techniques (used cautiously)
- Hand-Over-Mouth Exercise (HOME):
- Rarely used now; placing a hand over the child’s mouth to gain attention.
- Ethically controversial and requires informed consent.

- Physical Restraint:
- Used only in extreme cases; involves using papoose boards or straps.
- Must be justified, documented, and done with consent.

4. Pharmacological Techniques
- Conscious Sedation, General Anesthesia:
- Reserved for very young, extremely uncooperative, or special needs children.
- Requires monitoring and specialized training.

Arathi Rao emphasizes non-pharmacological and communicative techniques as first-line approaches, focusing on building trust and reducing fear in the dental setting.

Primary Resistance in Cavity Preparation

- Definition: The shape and form of the cavity designed to withstand occlusal forces without fracture.
- Key aspects:
- Flat pulpal and gingival floors
- Preservation of sound tooth structure at the cavity walls
- Adequate thickness of restorative material
- Proper placement of cavity walls at right angles to occlusal forces

Reference: The textbook of Operative Dentistry by Nisha Garg (Chapter: Cavity Preparation)

Classification of Cavity

G.V. Black’s Classification:
- Class I: Pits and fissures on occlusal surfaces of molars and premolars, buccal or lingual pits of molars, lingual pits of maxillary incisors.
- Class II: Proximal surfaces of premolars and molars.
- Class III: Proximal surfaces of incisors and canines without involving the incisal edge.
- Class IV: Proximal surfaces of incisors and canines involving the incisal edge.
- Class V: Cervical third of the facial or lingual surfaces.
- Class VI: Incisal edges of anterior teeth and cusp tips of posterior teeth.


Reference: The textbook of Operative Dentistry by Nisha Garg (Chapter: Cavity Preparation)

The hybrid layer is formed when resin penetrates demineralized dentin.

(The textbook of operative dentistry by Nisha Garg) 

GIC releases fluoride, offering anti-cariogenic benefits, making it suitable for non-invasive ART techniques.

Over vs Under Triturition of Amalgam

Over Triturition:
- Causes: Excessive mixing time or speed.
- Effects: Amalgam becomes too wet, sticky, and shiny.
- Result: Difficult to handle, decreased strength, increased mercury content leading to more corrosion and marginal breakdown.

Under Triturition:
- Causes: Insufficient mixing time or speed.
- Effects: Amalgam appears dry, crumbly, and grainy.
- Result: Poor cohesion, decreased strength, increased porosity, and easier fracture.

Reference: The textbook of Operative Dentistry by Nisha Garg (Chapter: Amalgam restoration)

APF gel (1.23%) is widely used due to high efficacy and compatibility with tooth enamel.

Fluoride Toxicity

1. Acute Toxicity
- Cause: Large fluoride ingestion in short time
- Symptoms:
- Nausea
- Vomiting
- Abdominal pain
- Diarrhea
- Hypocalcemia
- Cardiac arrhythmia
- Management:
- Induce vomiting
- Administer calcium gluconate
- Supportive care

2. Chronic Toxicity
- Cause: Long-term excessive fluoride intake
- Symptoms:
- Dental fluorosis (mottled enamel)
- Skeletal fluorosis (joint stiffness, bone pain)
- Prevention:
- Controlled fluoride use
- Avoid excess intake

Mechanism of Action of Fluoride

1. Remineralization:
Fluoride promotes the remineralization of enamel by forming fluorapatite, which is more resistant to acid dissolution than hydroxyapatite.

2. Inhibition of Demineralization:
Fluoride reduces enamel solubility in acid, thus preventing mineral loss during acid attacks.

3. Antibacterial Effect:
Fluoride inhibits bacterial enzymes in plaque, reducing acid production by cariogenic bacteria.

4. Effect on Plaque:
It interferes with bacterial metabolism and plaque formation, reducing cariogenic potential.

Reference: The textbook of Operative Dentistry by Nisha Garg (Chapter: Fluoride)

Fluoride replaces Hydroxyl Ion, not Calcium Ion.

Principles of Access Cavity Design
(The textbook of Endodontics by Nisha Garg – Access Cavity Preparation)

1. Straight-Line Access
2. Complete Removal of Pulp Chamber Roof
3. Conservation of Tooth Structure
4. Locate All Canal Orifices
5. Avoid Undercuts and Ledges
6. Outline Form Specific to Tooth Type
7. Prevention of Procedural Errors

Arrested Caries

- Definition: Caries lesions that have stopped progressing and become inactive.
- Characteristics:
- Hard, dark brown or black surface.
- No further demineralization or cavity expansion.
- Often covered by plaque or calculus.
- Clinical Importance: Arrested caries do not require operative treatment but need monitoring.
- Mechanism: Remineralization and loss of cariogenic environment lead to arrest.

Reference: The textbook of Operative Dentistry by Nisha Garg (Chapter: Caries)

pH Values in Relation to Caries 

- Critical pH for enamel demineralization: 5.5
- Critical pH for dentin demineralization: 6.2 - 6.7

Streptococcus mutans is widely recognized as the primary organism for initiation of caries because:

1.It adheres strongly to enamel surfaces using glucans produced from sucrose.
2.It ferments dietary sugars (especially sucrose) to produce acids (mainly lactic acid).
3.It is aciduric — survives and thrives in a low pH environment.
4.It is acidogenic — produces significant acid that demineralizes enamel.


Reference: The Textbook of Operative Dentistry by Nisha Garg

Structures Overlapped in Dental Radiology causing artifact :

1. Zygomatic arch
2. Hyoid bone
3. Nasal septum
4. Maxillary sinus walls
5. Palatal tori
6. Styloid process
7. Mandibular canal
8. Mental foramen
9. Cervical spine
10. Soft tissues of the neck (e.g., epiglottis, tongue)
11. Air spaces (nasopharyngeal, oropharyngeal)
12. Nasal conchae
13. Superimposition of teeth roots
14. External oblique ridge
15. Mylohyoid Ridge 

Here’s a list of 'radiation hazards' relevant to dentistry:

1. Somatic Effects (Affect the individual exposed)
- Skin erythema (reddening)
- Hair loss (epilation)
- Cataract formation
- Radiation burns
- Reduced salivary gland function
- Oral mucositis (in high-dose exposure)
- Delayed wound healing
- Immunosuppression

2. Stochastic Effects (Probability increases with dose; no threshold)
- Carcinogenesis (oral cancer, leukemia)
- Genetic mutations
- Chromosomal aberrations

3. Deterministic Effects (Have a threshold dose; severity increases with dose)
- Radiation dermatitis
- Cataracts
- Oral tissue necrosis (in radiation therapy context)

4. Reproductive Hazards
- Infertility (with high-dose exposure to gonads)
- Fetal malformations (if pregnant woman exposed)

5. Developmental Hazards
- Growth disturbances (in children)
- Dental anomalies (if exposure occurs during tooth development)

6. Occupational Hazards for Dental Professionals
- Cumulative low-dose exposure risks
- Increased cancer risk over long term
- Thyroid dysfunction
- Genetic impact on offspring

Radiographic Techniques in Dentistry:

1. Intraoral Radiographic Techniques
- Periapical (Paralleling technique)
- Periapical (Bisecting angle technique)
- Bitewing technique
- Occlusal radiography

2. Extraoral Radiographic Techniques
- Panoramic radiography (OPG)
- Lateral cephalometric radiograph
- Posteroanterior (PA) skull view
- Waters’ view (Occipitomental)
- Submentovertex view
- Reverse Towne’s view
- Lateral oblique view of mandible

3. Advanced Imaging Techniques
- Cone Beam Computed Tomography (CBCT)
- Conventional CT
- MRI (for soft tissue lesions)
- Digital radiography (Direct & Indirect)

4. Special Techniques
- Sialography
- Contrast radiography
- TMJ radiography

Radiation Protection Measures:

1. For Patient:
- Use of lead apron and thyroid collar
- Use of high-speed films or digital sensors
- Proper collimation (preferably rectangular)
- Use of E/F-speed film
- Minimum exposure time
- Proper positioning and technique to avoid retakes

2. For Operator:
- Maintain distance of at least 6 feet from X-ray source
- Stand behind protective barrier or wall
- Never hold film in patient’s mouth
- Use dosimeter badges for exposure monitoring

3. Equipment Safety:
- Use of aluminum filters to absorb soft X-rays
- Regular equipment maintenance
- Use of appropriate exposure settings

4. Legal/Administrative Measures:
- Compliance with radiation safety norms
- Staff training on radiation hazards
- Record keeping of exposures and maintenance

Health Indicators 

Morbidity Indicators:
- Incidence rate
- Prevalence rate
- Notification rate
- Attendance rates at health facilities
- Admission, readmission, discharge rates
- Duration of hospital stay
- Spells of sickness or absence
- Outpatient/inpatient ratio

Mortality Indicators:
- Crude death rate
- Age-specific death rate
- Sex-specific death rate
- Infant mortality rate
- Neonatal mortality rate
- Post-neonatal mortality rate
- Under-5 mortality rate
- Maternal mortality ratio
- Proportional mortality rate
- Case fatality rate

Disability Indicators:
- Disability rate
- DALY
- QALY

Nutritional Indicators:
- Anthropometric measurements
- Birth weight statistics
- Nutritional deficiency rates
- Food consumption data
- Breastfeeding rates

Utilization of Health Services Indicators:
- Proportion using health services
- Immunization coverage
- Antenatal care coverage
- Skilled birth attendance
- Hospital bed occupancy rate

Socioeconomic Indicators:
- Literacy rate
- Income per capita
- Employment rate
- Housing and sanitation
- Dependency ratio

Health Policy & Service Indicators:
- Doctor-population ratio
- Nurse-population ratio
- Health expenditure per capita
- Number of health centers per population

Reference :  Textbook of Preventive & Community Dentistry by SS Hiremath 

Communication Barriers – Study Sheet (S.S. Hiremath)

1. Physiological Barriers
- Hearing impairment
- Speech defects
- Physical illness
- Effect: Difficulty in receiving or interpreting messages

2. Psychological Barriers
- Fear, anxiety, mistrust
- Emotional disturbances
- Effect: Affects patient’s receptiveness and cooperation

3. Environmental Barriers
- Noise, poor lighting, lack of privacy
- Effect: Interrupts concentration and understanding

4. Cultural & Social Barriers
- Language differences
- Different beliefs or customs
- Effect: Misunderstanding or rejection of health advice

5. Semantic Barriers
- Use of technical/dental terms
- Complex language
- Effect: Misinterpretation and confusion

6. Organizational Barriers
- Poor communication planning
- Conflicting instructions
- Effect: Miscommunication, delays, dissatisfaction

How to Overcome Barriers:
- Use simple, clear language
- Ensure quiet, private setting
- Be empathetic and culturally sensitive
- Use visual aids
- Ask for feedback to ensure understanding

EDTA chelates calcium ions and removes the smear layer from canal walls, enhancing penetration of irrigants and sealers.

Gutta-percha cones are used to fill and seal the root canal system three-dimensionally, preventing reinfection.

Early signs of systemic toxicity include ringing in the ears (tinnitus), metallic taste, and numbness around the lips.