Dental Infection Control Practices

Practical Surgery 1: Maxillary Nerve

• The maxillary nerve is the second branch of the trigeminal nerve (the fifth cranial nerve), which is the largest cranial nerve.
• It is purely sensory, supplying sensation to the middle third of the face.
• It has a course beginning anterior to the trigeminal ganglion in Meckel's cavity, passing through the lateral wall of the cavernous sinus, the foramen rotundum and entering the pterygopalatine fossa, then continuing into the inferior orbital fissure, the infra-orbital groove, and finally the infraorbital canal, terminating in the face with three branches (inferior palpebral, nasal lateral, and superior labial).
• Its primary functions include sensation from the maxillary area of the skin of the middle face, maxillary teeth of the upper jaw, mucous membranes related to the maxilla, nasal cavity, and sinuses, and the palate.

Branches of the Maxillary Nerve

• In the cranium (cranial cavity):

  • The middle meningeal nerve supplies the meninges of the middle cranial fossa.

• From the pterygopalatine fossa:

  • 2 ganglionic roots forming the pterygopalatine ganglion (sphenopalatine ganglion) which provides 5 branches:
    • Orbital branches
    • Nasopalatine nerve → supplies palatal mucosa related to anterior teeth
    • Greater palatine nerve supplies the hard palate
    • Lesser palatine nerve supplies the soft palate
    • Pharyngeal branch of maxillary nerve
  • Zygomatic nerve, passing through the inferior orbital fissure, divides into 2 branches:
    • Zygomaticotemporal nerve → supplies skin of the anterior temporal region, communicating with lacrimal nerve
    • Zygomaticofacial nerve → supplies skin of the zygomatic bone.

• From the posterior superior alveolar nerve: (2 or 3 nerves)

  • This nerve originates in the pterygopalatine fossa, passes through pterygomaxillary fissure, and enters the maxilla.
  • It supplies the upper gum, mucous membrane of the cheeks and mucous membrane of maxillary sinuses.
  • It then supplies maxillary molars

• Infraorbital nerve passing through infraorbital groove & infraorbital canal:

  • The infraorbital nerve branches out to provide nerve supply to the upper teeth and the linings of the maxillary sinus.

  • Middle superior alveolar nerve → main nerve supply to upper premolars

  • Anterior superior alveolar nerve → main nerve supply for upper anterior teeth

Branches for sensation on the face

• Inferior palpebral nerve → skin of lower eyelid.
• Lateral nasal nerve → side/lateral of nose, nasal vestibule
• Superior labial nerve → cheek, upper lip and labial glands, oral vestibule lining.

Nerve Supply for Maxillary teeth

• Anterior superior alveolar nerve → anterior teeth (1,2,3)
• Middle superior alveolar nerve → premolars (4,5) & mesiobuccal root of 1st molar (6)
• Posterior superior alveolar nerve →Upper molars (6,7,8) except mesiobuccal root of 1st molar(6)
• Greater (anterior) palatine nerve → Maxillary molars (6,7,8) & premolars (4,5)
• Nasopalatine nerve → Maxillary anterior teeth (1,2,3)

Practical Surgery 2: Mandibular Nerve

• The mandibular nerve is the third division of the trigeminal nerve (V3).
• It is a mixed nerve composed of sensory and motor roots.
• The sensory root arises from the trigeminal ganglion, and the motor root arises from the trigeminal motor nucleus in the pons. The roots join in the foramen ovale.
• Major branches & relations begin about 1/2 cm from the foramen ovale.
• Branches from the mandibular nerve can provide sensory and motor functions to major areas of the face including skin, temporalis muscles, buccinator muscle.
• Branches from the anterior division provide predominantly motor functions, while branches from the posterior division primarily are sensory.

Branches of the Mandibular Nerve

• Branches of the main trunk (1 sensory + 1 motor):

  • Nervous spinosus (sensory), that supplies the dura mater of the middle cranial fossa
  • Nerve to the medial pterygoid (motor), that supplies the medial pterygoid, tensor palati, and tensor tympani muscles

• Branches from the anterior division (3 motor + 1 sensory):

  • Masseteric nerve (motor): supplies the masseter muscles.
  • Nerve to the lateral pterygoid (motor): supplies the lateral pterygoid muscles.
  • Deep temporal nerves (motor): supplies the temporalis muscles
  • Buccal nerve{Long buccal} (sensory): supplies skin over the buccinator muscle & mucous membrane of the cheek & gums opposite molar teeth

• Branches from the posterior division (3 sensory + 1 motor):

  • Auriculotemporal nerve (sensory): supplies the TMJ, parotid gland, temporal region.
  • Lingual nerve (sensory): carries general sensations from the mouth floor & lingual gums, tastes from anterior 2/3 of the tongue and secretomotor parasympathetic fibers to submandibular & sublingual gland.
  • Inferior alveolar nerve (sensory): the largest branch, supplying lower molar teeth, it runs through the mandibular foramen and mandibular canal, then dividing into two branches (mental & incisive nerves) which supply the gingiva opposite to premolar & anterior teeth
  • Nerve to the mylohyoid (motor): supplies the mylohyoid muscle and anterior belly of digastric muscle.

How to anesthetize mandibular teeth

• Molar teeth → Inferior alveolar nerve for teeth, lingual nerve for lingual mucosa, and buccal nerve for buccal mucosa
• Premolar teeth → Inferior alveolar nerve for teeth, lingual nerve for lingual mucosa, and mental nerve (from inferior alveolar nerve) for buccal mucosa
• Anterior teeth → Incisive nerve (branch from inferior alveolar nerve) for teeth, mental nerve (branch from inferior alveolar nerve) for labial mucosa and lingual nerve for lingual mucosa. Interlacing fibers overlap from opposite side (incisive nerve)

Infection Control in Dental Clinics

• Importance of infection control in dentistry to prevent transmission of pathogens between patients and dental staff.
• Modes of transmission: Direct contact with blood and body fluids, indirect (contaminated instrument or surfaces), contact with mucous membranes (eyes, nose, mouth), inhalation of airborne microorganisms
• Standard precautions should include hand hygiene, Personal Protective Equipment (PPE) use, sterilization of equipment, aseptic techniques, waste management, control of environmental surfaces, and injury prevention.
• Hand Hygiene → Using alcohol-based hand rubs is optimal; with plain or antimicrobial soap, lather and scrub for 20 sec (include areas like fingers, under the nails, & the tops of your hands), rinse & dry hands thoroughly, turning off the tap.

Personal Protective Equipment (PPE)

• Surgical masks & protective eyewear & face shields: To protect mucous membranes from exposure to infectious materials..
• Protective clothing: Wear gowns, lab coats, or uniforms that cover skin and can be soiled with blood, saliva or infectious material. Change the barriers/clothing often or when soiled. Remove before leaving.
• Remove hand accessories: Rings, bracelets, watches, etc are difficult to disinfect, can tear gloves and can be used for introducing blood or saliva to wound/open areas.
• Gloves: Use a fresh set for each patient.. Remove gloves after patient care & do not reuse them, and avoid touching contaminated surfaces.

Sterilization of Equipment

• Critical instruments: These penetrate mucous membranes, contact bone, bloodstream or other normally sterile tissues (e.g., surgical instruments, scalpel blades, periodontal scalers and surgical dental burs). → Autoclave between uses or use sterile, disposable devices (scalpel blades & needles).
• Semi-critical instruments: Contact mucous membranes, but don't penetrate tissue (e.g., dental mouth mirrors, amalgam condensers, and dental handpieces). → Autoclaving or High-Level disinfection.
• Non-critical items: Contact intact skin(e.g., X-ray heads, facebows, pulse oximeters, blood pressure cuffs). → Cleaning and disinfection using a low to intermediate level disinfectant.

Environmental Infection Control

• Clinical contact surfaces: (High potential for direct contamination from spray or spatter) → handle of the light, units, bracket table, etc. need cleaning & wrapping
• Housekeeping surfaces: (Minimal risk of disease transmission) →cleaning and decontamination procedure may not be as strict as clinical surfaces

Medical waste management

• Medical waste should be disposed of in safety boxes. to avoid potential injury.

Injury Prevention

• Using instruments instead of fingers to retract or palpate tissue for working on the patient during procedures.
• Safe use of one-handed needle recapping procedures.

Armamentarium Techniques for Local Anaesthesia

• Needles: Types by length (extra short, short, long), gauge (thickness which relates to the thinnest-higher gauge number), and the bevel (part where the numbing solution comes out)
• Syringe: Types include: metal, plastic, glass.
• Local anesthetic cartridges: Ester or amide groups of local anaesthetics.
• Auxiliary materials: Sterile materials for painting/disinfection, cotton applicators for drying, aseptic solution (e.g., betadine), or topical anaesthesia

Types of Local Anesthesia

• Topical: Gel or spray.
• Infiltration: For terminal nerve endings.
• Field block: Branches of the main nerve
• Nerve block: Blocks a well-known main nerve.
• Pulpal anesthesia: of teeth when treatment involves only 1 or 2 teeth
• Soft tissue anesthesia: when indicated for surgical procedures in a limited area

Maxillary Anesthesia Techniques

• Local infiltration technique(paraperiosteal or supraperiosteal): Diffusion of local anesthetic through the periosteum and the foramina to reach the nerve endings in cancellous bone.
• Buccal infiltration injection - Using a 27-gauge short needle, insert with a 45-degree angle, and advance until the bevel is at or near the tooth's apical area. Deposit the medicine slowly.
• Palatal infiltration injection Insert the needle midway between the tooth's cervical margin & the midline of the palate, inserting it distal to the target tooth, to avoid reaching the lesser palatine nerve..
• Greater Palatine Nerve Block: Anesthetizing the nerve at the foramen, using a short needle.
• Nasopalatine/Incisive Nerve Block: Anesthetizing the nerve at the nasopalatine foramen → reaching all six anterior teeth at once.
• Posterior Superior Alveolar Nerve Block: Used when treatment involves 2 or more molars, supraperiosteal injection is contraindicated. (e.g., with infection or acute inflammation), When supraperiosteal injection is ineffective.
• Infraorbital Nerve Block: Anesthetizing the infra-orbital nerve and its branches
• Maxillary nerve block → anesthetizing main trunk of the maxillary nerve & its branches, including branches of the spheno-palatine ganglion. The whole area of the maxilla will be anesthetized by this injection. There are two techniques to use this approach:
  • High Tuberosity Technique
  • Greater palatine canal approach

Mandibular Anesthesia Techniques

• Inferior Alveolar Nerve Block: Anesthetizing the inferior alveolar nerve before it enters the mandibular foramen, affecting also the mental & incisive branches..
• Mental & Incisive nerve Block: Affects the mental nerve & lower lip, also the mucolabial fold anterior to the mental foramen. Use a posterior direction to avoid problems in the inferior alveolar canal
• Long Buccal Nerve Block → a branch of the ant division of mandibular nerve → runs between the 2 heads of the lateral pterygoid muscle, reaching the anterior masseter at the level of the third molar occlusal plane, and then innervates the buccal mucosa.
• Lingual Nerve Block: Anesthetizing the lingual nerve which carries general sensations, tastes from the ant 2/3 of the tongue & other important fibers.
• Mandibular nerve block (The Gow – Gates Technique) → this technique fully reclines the patient to allow visibility to the maxilla & mandible for nerve block procedure. The technique of using the thumb in the mouth & using imaginary lines as guides will show the operator how much to move the needle.
• Vazirani-Akinosi Closed-Mouth Mandibular Block a useful method, especially for patients with limited mouth opening capacities.. it is done through the buccinator muscle area in the pterygomandibular space.

Surgical Instruments 8: Dental Forceps

• Upper anterior forceps (straight): Used for upper anterior teeth.
• Upper premolar forceps: Used for upper premolars.. Designed to access teeth in accessible areas.
• Upper molar forceps: Used for upper molars, with or without root. There are 2 types:
  • upper right & upper left molars
• Upper remaining root forceps (Reed's Forceps): Used after extraction of upper roots.
• Upper third molar forceps: Used for removal of upper third molars when it is a full crown or remaining root.
• Lower anterior forceps / lower remaining root forceps: Used for lower anterior & lower roots extraction.

Practical Surgery 6: Elevators

• Definition: Dental elevator is a surgical tool for moving teeth/roots that cannot be extracted by forceps.
• Parts: The elevator is composed of a blade, shank, and handle.
• Indications:
  • Luxation of teeth
  • Removal of remaining roots
  • Removal of broken roots
  • Removal of inter-radicular bone when the roots are separated.
• Rules for use: Never use an adjacent tooth as a fulcrum (except for some specific cases), avoid using the buccal plate of bone as a fulcrum except during extraction of lower 2nd & 3rd molars. Use a finger guard to avoid damaging adjacent tissue when using the elevator. Avoid slipping the elevator by supporting the shank with the index finger, avoid using the elevator on the maxilla bone since it is spongy & support of the maxillary sinus should be avoided with a very light & delicate touch.
• Principles of how the elevator works:
  • Wedge: The elevator wedges into the tooth socket to dislodge the root.
  • Lever: The elevator lever principle works similarly to a seesaw; greater force in a smaller portion causes the root to be moved towards the alveolar region/bone opening.
  • Wheel and axle: The crossbar elevator principle uses the larger handle of the instrument, transferring the force applied to the smaller part of the blade.

Practical Surgery 7: Extraction of Teeth

• Requirements of Ideal Extraction: Satisfactory access and visualization (bloodless field), un-obstructed pathway, controlled force, apical grip on the tooth.
• Patient position: Maxillary & mandibular teeth extraction require different chair positioning to optimize access.
• Surgeon position: Maxillary & anterior mandibular need the dentist in front of the patient for proper access to the teeth & lower mandibular need the operator position behind the patient (either right or left based on handedness), for all teeth the surgeon should be positioned in front of the patient to the right, except lower posterior teeth when it is necessary to be behind the patient.
• Technique of forceps extraction: The forceps should be held correctly by the right hand & supported with the left hand below the joint for better control during extraction procedures.
• Displacement of tooth from its socket: The displacement technique needs to be tailored for each tooth type; Lateral or bucco-lingual movements are used for most teeth, while proper rotation is needed for specific teeth.

Practical Surgery 8: Surgical Instruments

• Surgical instruments: Include instruments used for extraction, local anaesthesia, holding the drapes, incising tissues, reflecting the mucoperiosteal flap, holding the soft tissues, keeping the mouth open, and removing pathological tissue.
• Instruments used to reflect the mucoperiosteal flap: Periosteal elevator. Has a pointed and a broad end to release and elevate the flap from the bone respectively..
• Hemostatic forceps: (artery forceps/ mosquito forceps), Used to control bleeding in a procedure. They are classified by size (large, medium, or small), and by shape (straight or curved).
• Tissue holding forceps (Allis's forceps): Used to grasp tissue to be removed or for biopsy. They are classified by toothed or smooth/ non-toothed types..
• Mouth Props: Used to hold the patient's mouth open during dental procedures..
• Curette/ Bone curette: Used to remove debris, tooth particles, and pathological tissues from the extraction site.
• Bone file: Used to smooth any sharp bony margins.
• Rongeurs forceps: Used to chisel/cut bone. They are side or side & end cutting types

Practical Surgery 10: Radiographs in Surgery

• Why radiographs are needed: To confirm diagnosis, aid in formulating proper treatment plans, guide during surgical procedures, monitor treatment results for follow-up & record for medico-legal purposes.
• Imaging techniques: Imaging of the oral cavity types include: Intraoral (periapical, occlusal, bitewing), and extraoral radiographs(panoramic, lateral cephalometric, lateral oblique, postero-anterior, reverse Towne view, standard occipito-mental [0° OM], 30° occipito-mental [30° OM] & Waters view).
• Indications for radiographs: Detection of lesions (cyst, granuloma, tumors, infections, fractures) in various bony structures, assessment of impacted/ unerupted teeth or locating roots. Also for monitoring/recording teeth/root conditions, before/after treatment.
• Radiographic signs of fracture: Tracking external borders of the bone (using lines) is a key technique
• Examples of fractures: Include lateral, oblique, para-symphyseal, angle, subcondylar fractures..

Practical Surgery 11: Instruments Used During Fracture Fixation

• Types of Reduction: Closed (manual correction) and Open (surgical correction)
  • Indications: Used for non-displaced and favorable fractures, mandibular fractures, coronoid process fractures.
  • Advantages: Closed is less invasive and expensive. Open allows for more precise and complete reduction
  • Disadvantages: Closed may not be suitable for all types of fractures & open approach involves greater injury & possibility of complications.
• Types of Fixation: Direct (across the fracture, using wires or bone plates) & Indirect (use the surrounding/adjacent structures/teeth as anchors to hold the fractured parts in position)
  • Direct fixation:
    • Interosseus wiring → passing wire through holes drilled on the bone fracture for interlocking
    • Bone plating → using plates and screws to reinforce and hold the bone fragments
    • Lag screws → Compression of fracture fragments. They only have threads at one end, thus causing the compressed bone fragments to meet
  • Indirect fixation:
    • Dental wiring (or eyelet and Ivy loop), Cap splints, Gunning splints.
    • Arch bars → Used to fasten the arches to each other and stabilize the fragments.
    • Cap splints → Acrylic or metal splints that are cemented onto teeth of the patient, usually used on patients who have lost most of their teeth due to trauma/diseases.
    • Gunning splints → Similar to cap splints, but it is used for patients who have lost their teeth to trauma/disease. Also used where upper & lower jaws are interconnected.

Test your knowledge on infection control practices in dental settings. This quiz covers modes of transmission, hand hygiene methods, and personal protective equipment. Assess your understanding of the precautions needed to ensure safety during dental procedures.