Week 1 Anatomy and Armamentarium
Total Drug volume
The standard volume of an LA drug is 1.8 ml The volume of drug expelled by one cartridge stopper length is a standardized unit that can be used for easy calculation of volumes of solution delivery. Each stopper deposited is approximately .2 ml of solution. Monitoring the distance the stopper moves can be used to determine the portion of solution expelled from a 1.8 ml cartridge
Infraorbital nerve
# 2 Branch of the fifth cranial nerve that affects the skin of the lower eyelid, side of the nose, upper lip, and mouth.
Mandibular Anatomy to know
- body, Ramus, angle of the mandible, coronoid process, Grand Isle, La Jolla, mandibular and mental foramen, coronoid process
Contents of a local anesthetic drug
- distilled water/ majority of solution - local anesthetic drug - vasoconstrictor drug if present - sulfite preservative one basal constrictor is present - sodium chloride for isotonic tissue compatibility
Palatal Anatomy to know
- incisive foramen, greater Palatine foramina, median Palatine suture, maxillary tuberosity - be able to describe the location of the greater Palatine foramen
Basic armamentarium for dental anesthesia
- mouth mirror which may also be used to cheek retract - devices for safe needle recapping and disposal - syringe - cotton pliers or hemostat - gauze squares for drying tissues and enhancing retraction - cotton swabs for application of topical anesthetic agents and predetermination of penetration sides and angles -Needles of appropriate gauge and length - cartridge of drugs - topical anesthetic agents
What makes a syringe an aspirating syringe?
- the ability to pull back on the plunger of the syringe is pulled back intentionally to create a "vacuum" so the healthcare provider is positive that the needle tip is located at the appropriate spot, away from blood vessels that should not be punctured or have LA deposited into.
Common needle gauges in dentistry
25 - Red Caps 27 - Yellow Caps 30- Blue Caps Selection of the gauge based on the depth of penetration necessary to reach deposition sites, on the relative risks of what is known as positive aspiration and on clinician preference. Factors impacting this Choice =needle deflection, ease and accuracy of aspiration and perceived patient comfort.
Anatomy of a local anesthetic needle
A- Needle Shaft with beveled tip B Cartridge penetrating end C D- Syringe Adaptor and E- Hub F- Needle Cap
Anatomy of a Dental Syringe
A- Thumb Ring B- Finger Grip C- Spring D- guide Bearing E- Piston w Attached Harpoon F- Harpoon G- Syringe Barrel H- Needle Adapter
Incisive nerve
Afferent nerve composed of dental branches from the mandibular anterior teeth and premolars that originated in the pulp. Incisive nerve merges with mental nerve just posterior to the mental foramen. Crossover innervation from the contralateral incisive nerve can also occur, which is important consideration when administering local anesthesia for the mandibular anterior teeth and premolars and Associated tissues
Buccal Nerve
Afferent nerve for the skin of the cheek and buccal mucosa. As well as the associated buccal periodontium. Usually Anesthetized with the Gow Gates
Inferior alveolar nerve
Afferent nerve formed from the merger of the mental nerve and incisive nerve. Carries afferent innervation for the mandibular teeth and Associated facial periodontium and gingiva of the mandibular anterior teeth and premolars as well as labial mucosa through is incisive and mental branches to the midline
Cartridge storage
All local anesthetic Solutions should be stored in cool dry areas at temperatures recommended in product inserts. If solutions have been overheated during shipping and handling the contents of the cartridge may appear cloudy or sediment may be visible If cartridges are stored in improved warming devices it is important to be aware that long-term storage at temperatures higher than typical room temperatures in May degrade the contents more quickly.
Cartridge labeling and coding
Both the trade and generic drug names are provided along with drug concentrations, dilutions of vasoconstrictor, the manufacturer, and expiration date, a local anesthetic drug color code band and the lot number and barcode.
Which comes first in assembling syringe - the needle or cartridge why?
Cartridge first and needle second to prevent cap leakage
Local anesthetic drug cartridges
Commonly referred to as a carpule. Cartridges used in the United States contain 1.8 mL of solution A dental cartridge has four components a cylindrical glass tube( A ) ; a rubber or silicone stopper( D ); aluminum end cap( C ); and a rubber diaphragm ( B )
Mental nerve
Composed of external branches that serve as afferent nerves for the chin, lower lip, and labial mucosa as well as the associated facial periodontium and gingiva of the mandibular anterior teeth and premolars to the midline.
Cartridge handling and expiration
Damage during shipment rarely occurs but it is important to visually examine each cartridge before administering its contents. Cartridges should be inspected for - integrity - Clarity of the solution - presence of large air bubbles - damaged or tarnished caps - damaged or leaking Stoppers - last expiration dates LA without VC have a shelf life of approximately 24 months. With 18 months
Air bubbles
During manufacturing, air bubbles are frequently trapped under the diaphragm when the aluminum cap is placed in the cartridge. These small bubbles are of little consequence because it will never pass through the needle. Cartridges should be discarded when larger bubbles are noted below the cap when held vertically. Large bubbles can result when Solutions have been frozen or contaminated.
Contents of anesthetic cartridges
Each cartridge contains a LA drug in solution. Powdered LA drug is mixed with hydrochloric acid to create an acidic salt for better water solubility. The hydrochloride salt of the drug is then added to distilled water which makes up the majority of the solution. When vasoconstrictors are included, sodium bisulfate is added as a preservative. Sodium bisulfate increase the acidity of the solution which can result in a burning sensation when administered. Additionally sodium chloride is included to improve tissue compatibility.
Integrity of cartridges and contents
Each cartridge should be examined before injection in order to confirm that the appropriate anesthetic and vasoconstrictors are being administered and that the solution has not expired. Problems with cartridges may include excessive air bubbles, leaking around the cap or stopper, distortion of Stoppers, difficulty advancing Stoppers and jamming of cartridges in the barrel
Anatomy of a local anesthetic needle part 2
Each needle has a flexible Hollow stainless steel shaft. This one piece shaft also referred to as a shank extends from the tip of the needle through the syringe adapter and hub to what is known as the cartridge penetrating end. The hollow portion of the needle is referred to as its lumen. The bevel is a diagonal cut that make the point of a needle. The cartridge penetrating end of the needle shaft opposite the bevel end pierces through the center of the diaphragm of the local anesthetic cartridge. The syringe adapter of the needle is the plastic or aluminum held through which the needle shaft passes. The Hub of a needle is the point at which the shaft joins and secures the needle to the syringe adapter.
V2 maxillary
Exits foramen rotundum The afferent nerve branches of the maxillary nerve carries sensory information for the maxillae and it's overlying skin, oral mucosa, maxillary sinuses, nasal cavity, palate, nasopharynx and part of the dura mater. Maxillary nerve branches into the IO Nerve, ASA Nerve, MSA Nerve, PSA Nerve, GP Nerve, Nasopalatine Nerve
V3 mandibular
Exits through foramen ovale Sensory and motor Included motor innervation to the muscles of mastication and sensory innervation to the mandibular teeth - Buccal nerve, lingual nerve, inferior alveolar nerve, mental nerve, incisive nerve,
Lingual nerve
Formed from afferent branches from the associated lingual periodontium and gingiva of mandibular teeth and from the body of the tongue. It first travels along the lateral surface of the tongue, then passes posteriorly passing from the medial to lateral side of the duct of the submandibular salivary gland.
Needle gauges
Gauge = diameter of lumen = Smaller # = larger opening. Bigger number = Smaller opening. Some clinicians preferred 25 gauge needles for injections where the risk of positive aspiration are greater. ( IA, PSA, M/I ) Many clinicians believe that injections administered with a 27 or 30 gauge needle causes less discomfort during insertion compared to 25 gauge needles despite comparisons and clinical studies that have demonstrated that patients are unable to feel the difference between larger and smaller gauge needles.
which foramen is located superior to the maxillary tuberosity?
Greater Palatine foramen
Response to needle sticks
If a needle stick or other puncture injury occurs all anesthetic procedures and treatment should be terminated and the injured tissues immediately and thoroughly washed with soap and water. The facility's exposure manager should be notified while appropriate first-aid is initiated. According to the CDC guidelines post-exposure management should include documentation and both the patient's record and the exposed individual health record.
Trigeminal Nerve (CN V)
Is composed of three divisions V1 ophthalmic V2 maxillary V3 mandibular the trigeminal nerve provides sensory information for the teeth and Associated tissues. The branches of the trigeminal nerve that are anesthetized before most possibly painful dental procedures include the maxillary nerve and Mandibular nerve. ( Mixed Nerve/ Sensory and Motor )
Describe the location of the mental foramen
Laterally and posteriorly on the surface of the mandible and usually inferior to the apices of the mandibular premolars
Greater Palatine nerve
Located between the mucoperiosteum and bone of the posterior hard palate. The GP nerve serves as an afferent nerve for the posterior hard palate and the associated palatal periodontium and gingiva of the ipsilateral maxillary posterior teeth. The GP nerve enters the greater Palatine foramen in the horizontal plate of the Palatine bone superior to the apices of the maxillary second or third molar. The opening of the greater Palatine foramen is a landmark for the administration of the GP block that anesthetizing has the GP nerve
Common needle length in dentistry
Needle length is selected based on the depth of penetration necessary to achieve successful anesthesia. LA needles are usually identified as Long - 32mm ( 1 1/2 inches ) Short - 25mm ( 1 inch ) Extra short - 12mm ( 1/2) Short needles are frequently used for injections that do not require significant depth of penetration Such as in filtrations in maxillary block techniques. Long needles are used for deposition sites at greater distances such as mandibular block techniques. Extra short needles can be used when penetrations are shallow sections palatal injection
Dental local anesthetic needles
Needles used for dental local anesthesia are slender, hollow, sterile stainless steel devices with sharp points intended to be attached to a syringe to inject local anesthetic Solutions. All needles are disposable, single patient devices. Needles are identified by their lengths and their diameters also referred to as in their gauge and are selected based on the injection techniques to be used.
Nasopalatine nerve
Originates in the mucosa of the anterior hard palate, palatal to the maxillary Central incisors. This nerve serves as an afferent nerve for the anterior hard palate and the associated palatal periodontium and gingiva of the maxillary anterior teeth bilaterally from maxillary canine to Canine as well as the nasal septal tissue. Both the right and left NP nerves enter the incisive Canal through the incisive foramen, therefore and administration of the NP block anesthetizes both the right and left at the same time.
V1 ophthalmic
Sensory - exits the skull via the superior orbital fissure -includes the top of nose, eye (lacrimal), and forehead (frontal)
Anterior Superior alveolar nerve
Serves as an afferent nerve for the maxillary Central incisors, lateral incisors and canines as well as Associated labial periodontium and gingiva to the midline part of the superior classes and the maxillary Arch Originates from Dental branches in the pulp of these teeth that exit through the apical foramen.
Middle Superior alveolar nerve
Serves as an afferent nerve for the maxillary premolars and the mesiobuccal root of the maxillary first molar and Associated buccal periodontium and gingiva if the nerve is present. Part of the superior Dental plexus in the maxillary Arch It is only present in approximately 28% of the population. If the MSA is not present the area is innervated by both the ASA and PSA nerves but mainly by the ASA.
Posterior Superior alveolar nerve
Serves as an afferent nerve for the mucous membranes of the maxillary sinus and the maxillary molars with the associated buccal periodontium and gingiva in most cases unless the MSA is present. The PSA nerve light the a essay and MSA are heart of the superior Dental plexus in the maxillary Arch
Dental local anesthetic syringes
Several different types of syringes are available in dentistry including those that are sterilizable stainless steel or plastic, disposable plastic, Manuel and self aspirating, ratcheted for delivering small doses Under Pressure, needleless and computer-controlled. The most common design in dentistry is the sterilizable, breech-loading, cartridge type, aspirating syringe because inadvertent intramuscular injection is a primary Hazard of local anesthetic injections. This syringe has easy to master aspirating capabilities to allow testing and visual inspection before drugs are administered.
Infraorbital nerve
The infraorbital nerve is an afferent nerve formed from the merger of cutaneous branches from the upper lip, the medial part of the cheek, side of the nose, and the lower eyelid. Passes into the infraorbital foramen of the maxilla with the opening serving as a landmark for the administration of the infraorbital block which one administered anesthetizes the IO nerve as well as both the anterior and middle Superior alveolar nerve
A patient complains that the left side of her face is paralyzed and her I won't blink. This occurs about 5 minutes following your inferior alveolar injection what happened and what do you tell your patient?
The needle was inserted too far posteriorly and may have entered the parotid gland which contains cranial nerve 7 which is the facial nerve. The paralysis will wear off slowly as the LA wears off
Leakage at the cap
When higher gauge needles are used there is an increased risk of leakage. The flexibility of higher gauge needles, deflection of the cartridge penetrating can occur when needles are loaded into a syringe. Inserting cartridges in the syringe when loading before screwing on needles can reduce the incidence of this type of damage.
Displacement of Stoppers
When stoppers are partially extruded from cartridges it is possible that freezing occured during shipping or storage or that contamination occurred during storage in disinfectant solution. Affected cartridges should be discarded
