Pretend you are a teacher preparing a quiz for the text I will provide. 
            Each quiz question should follow the format below. 
            Ensure that you carefully recheck the questions and answers for accuracy. 
            The output should be a ready-to-use list of dictionaries for the Python eval function:

            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
                    "answer": INDEX_OF_CORRECT_ANSWER_IN_OPTIONS_LIST,
                    "explanation": "EXPLAIN WHY THE ANSWER IS CORRECT"

            ]

            Text:
            < 3 mm.  
                         2) Adequate keratinized gingival tissue. 
                         3) No bleeding on probing. 
 
 
 
     • Steps:  
• The finish line is prepared at the level of the gingival crest. 
• A torpedo-nosed diamond with water spray → extend the finish line subgingivally 
→ while the air coming from the high-speed hand-piece retract the gingival. 
3) Electrosurgery: 
 
 
 
• An electrosurgery unit may be used for minor tissue removal before impression.   
• A high frequency current (1 - 4 million Hz [1 Hz = 1 cycle/ second) →  
pass through the tissue from a large electrode to a small one →  
rapid localized polarity changes → cell breakdown (cutting) →  
then a coagulation → so the blood vessels are narrowed. 
• Advantages: In one technique, 1) the inner epithelial lining of the gingival 
sulcus is removed → improves access for a subgingival crown margin.  
2) Effectively control postsurgical hemorrhage  
    (provided that the tissues are not inflamed).  
• Disadvantage: → need experienced hands →  
   to avoid destruction of the periodontium, due to over deepening of the sulcus. 
   Unfortunately, there is the potential for gingival recession after treatment. 
90
 
     • Contraindication: In patient with:  
1) An electronic medical device (e.g., a cardiac pacemaker, insulin pump, or 
transcutaneous electrical nerve stimulation [TENS] unit). 
Although newer devices are designed to → deflect the unwanted current flow 
2) A delayed healing (e.g under a radiotherapy or a debilitating disease). 
3) A thin attached gingiva on the labial surface of the maxillary canine. 
• Steps:  
• Profound soft tissue anesthesia is mandatory.  
• Adjust the current intensity because:  
▪ If ↑ density current → spark in the patient's mouth 
▪ If ↓ density current → not cutting the tissue properly. 
• Start with the labial then → mesial → lingual → distal finally. 
• Hold the electrode parallel to the long axis of the tooth. → A water irrigation. 
• After removal of hyperplastic tissue → make mechano-chemical displacement. 
• The sulcus should be irrigated with hydrogen peroxide before placing the cord 
• The following facts should be considered before electrosurgery is attempted: 
• For restorative procedures, an unmodulated alternating current mode is 
recommended to set, because it ↓ damage to deeper tissues. 
• A thin wire or slightly tapered electrode is best for sulcular enlargement. 
• Gingival contouring is usually performed with a loop electrode.  
• The electrode should be passed rapidly through the tissue with a single light 
stroke & kept moving at all times.   
X It should not be used with metal instruments, because contact could cause → 
electric shock. (Plastic mirrors & evacuation tubes are available.) 
X The electrode must not touch any metallic restoration.  
   Contact lasting just 0.4 second → irreversible pulpal damage in dogs. 
• If the tip drags, the instrument is at too low a setting → the current should be ↑.  


            Quiz: