Chairside Assisting for Dental Assisting Exam Study Guide (page 3)
Practice problems for this study guide can be found at:
The dental office has many exciting areas in which to be a team member. Chairside assisting is an example of one such area. Assistants are utilized to their fullest capabilities. They must possess extensive knowledge in order to truly be effective at the chair. Dentists appreciate assistants who can anticipate their needs as operators and help them treat their patients. Efficient chairside assistants will increase the overall production of dental practices by aiding dentists in completing their procedures more quickly and more effectively.
Concepts and Skills
Knowledge of the following concepts and skills are necessary to become a licensed, highly skilled, and efficient chairside dental assistant. Chairside assisting is divided into ten main topics:
- Layout of a Dental Office
- Equipment in the Operatory (Treatment Room)
- Chair Positions
- Light Positions
- Clock Concept of Operating Zones
- Delivery of Dental Care
- Local Anesthetics and Analgesics
- Dental Support Aides
- Other Duties of Dental Assistants
- Dental Specialties
Layout of a Dental Office
A dental office can be organized in many ways. Some dentists prefer to work out of many operatories, while others will choose to work out of two treatment rooms. All offices will have the areas listed below. An informed assistant should be cross-trained to assist the dentist in the best way possible.
Patients enter this area first when arriving at the dental office. First impressions are important. This area can be decorated in any way the dentist chooses, but it should be welcoming and calming. It is important to straighten up the reception area continually throughout the day.
The front desk handles the business operations of the dental office. The assistant at the front desk is responsible for making appointments, answering the phone, insurance billing, patient invoicing, treatment-plan presentation (in some offices), and handling all financial matters.
Operatory or Treatment Rooms
This is where all dental services are performed. The dentist will typically work out of several rooms, while the hygienist works out of one assigned treatment room.
This area has many uses. Dental appliances can be fabricated here or sent to an outside lab if the dentist chooses. Lab cases can be stored here, and, if needed, this area can serve as overflow storage for back stock. There is specialized equipment found in the lab, such as a dental lathe and model trimmers.
Sterilization Area (Central)
This area is often referred to as “Central” because most dental offices are arranged to situate the sterilization area in the middle of the office, and all operatories feed into this area. Instruments are processed here using an autoclave or a similar type of sterilizer.
This area serves as a private area for the dental team members. Purses, lunches, and other personal belongings should be stored here during the workday.
Dentist’s Private Office
This area is where the dentist will be able to have privacy while reviewing and signing patient charts and for other private matters.
Equipment in the Operatory (Treatment Room)
The operatory, or treatment room, is the heart of the dental operation. It must be designed for efficiency and safety. The equipment in the operatory is divided into ten areas: light, dental chair and controls, portable unit, operator’s equipment, table top, rheostat, assistant’s stool, operator’s stool, operatory sink, and operatory computer.
Each operatory is equipped with an overhead light to aid the dental team with illumination into the oral cavity. Some lights have a dimming switch to use while placing light-sensitive materials. Changing the position of the light is the responsibility of the dental assistant.
Dental Chair and Controls
There are many types of dental chairs from which the dentist can choose. Since sit-down dentistry is most common today, most chairs are built for that purpose. Controls can be located in any area of the chair the dentist chooses. Currently, the most common way to control a dental chair is via foot controls. These controls can be pre-programmed to the positions the dentist prefers. The patient dental chair is contoured for the patient’s comfort. Newer models come with a massager and heat. The chair can be positioned in one of three ways: upright (used for taking impressions, exposing dental radiographs, and seating and dismissing the patient), supine (patients are reclined on their back), and subsupine (used for emergency situations).
The portable unit consists of the high-volume evacuator (HVE), the saliva ejector, and the air/water syringe (triplex syringe).
High-Volume Evacuator (HVE)
This is a high-speed suction device used by the assistant for removing debris, particles, and large amounts of water very quickly from the oral cavity.
This is a slow-speed suction device used by assistants for removing saliva only.
Air/Water Syringe (Triplex Syringe)
This device is capable of performing three functions. It can blow air, spray water, or “blast” a combination of air and water. The assistant utilizes this device while handling the HVE or saliva ejector.
The dentist’s equipment includes two types of hand pieces—high-speed and low-speed—as well as the air/water syringe.
High-Speed Hand Piece
This is commonly known as the drill. This piece of equipment is used by the dentist to prepare the tooth to receive a restoration.
Low-Speed Hand Piece
This piece of equipment is used by the dentist, along with the high-speed hand piece, to remove soft decay, polish a restoration, or complete a prophy.
This is where the assistant will place the instruments on the tray or in their cassette for the specific procedure. The table top is also known as the “mobile cart.”
This “foot pedal” controls the dental hand pieces.
This chair is designed specifically for the way an assistant sits at the dental chair. The stool is equipped with wheels and castors, a comfortable cushion, a lever to adjust the height, a foot ring, and often a belly bar for abdominal support.
This chair is designed specifically for the operator and the way she or he is positioned at the dental chair. This stool has a low adjustable backrest, a comfortable cushion, a lever to adjust both the backrest and height, and wheels and castors. There is never a ring on an operator’s stool. The dentist should be able to sit with his or her feet flat on the floor. For maximum visibility, the dental assistant’s stool should be four to six inches above that of the operator.
Each treatment room has at least one sink. Typically, there will be a sink on both the operator’s side and the assistant’s side.
Today’s operatory is usually equipped with a computer that runs dental office software. It can be utilized for one or all of the following:
- accessing the patient’s electronic chart
- digital X-rays
- intraoral images
- treatment plan for the patients
Dental chairs are the centerpiece of the operatory. They are adjustable to accommodate patients of all shapes and sizes. The three main positions are upright, supine, and subsupine.
The patient enters and leaves the dental chair in the upright position.
Dental treatment is performed in this position. The supine position places the patient flat on his or her back, with the head in line with the knees.
Dental treatment can be performed in this position if the dentist desires. The subsupine position places the patient’s head below her or his knees. This position also places the patient’s head directly in the operator’s lap. This is used for emergencies.
The operating light is an essential part of the equipment in the treatment room. It must be placed correctly to illuminate the area to be treated. There are two main light positions: maxillary and mandibular.
The light is positioned over the patient’s chest. Once the light is switched on, the beam should be directed toward the maxillary by gently pulling the light forward to the patient’s chin and then tipping it upward.
The light is positioned over the patient’s chest. Once the light is switched on, it should be pulled forward until it is directly over the patient’s mouth. The beam should be shining directly onto the mandibular teeth.
Clock Concept of Operating Zones
The dentist and assistant must work in harmony as a coordinated team. Operating zones define what activities take place in which areas. These zones are defined based on the hands of a clock. There are four defined zones: static zone, assistant’s zone, transfer zone, and operator’s zone. These zones differ for right-handed and lefthanded operators.
The four clock zones (based on clock positions) for the right-handed operator are as follows:
- 12–2 = Static Zone
- 2–4 = Assistant’s Zone
- 4–7 = Transfer Zone
- 7–12 = Operator’s Zone
12–2 = Static Zone
This is the clock zone where very little occurs.
2–4 = Assistant’s Zone
This is the clock zone where the assistant sits while assisting for chairside procedures.
4–7 = Transfer Zone
This is the clock zone where instrument transfer takes place. The assistant hands instruments and medicaments from the instrument tray to the operator through this zone.
7–12 = Operator’s Zone
This is the clock zone where the operator sits and performs all dental procedures.
A left-handed dentist also has the four operating zones, but they are reversed.
- 12–5 = Operator’s Zone
- 5–8 = Transfer Zone
- 8–10 = Assistant’s Zone
- 10–12 = Static Zone
The descriptions of these zones are the same as those for the right-handed operator. However, the clock times are switched.
Delivery of Dental Care
Four-handed dentistry involves the operator and one assistant working together at the chair, while six-handed dentistry involves the dentist and two assistants working together at the chair. One assistant is the chairside assistant, and the other is the roving assistant. The chairside assistant is responsible for patient safety and for maintaining a clean, debris-free environment in the oral cavity. The roving assistant is responsible for instrument transfer, mixing of materials, and the pace of the procedure.
Techniques of Four-Handed Dentistry
Four-handed dentistry is also known as team dentistry because the dentist and the assistant work closely together in a coordinated manner.
Various grasps are utilized by the operator depending upon the instrument of choice. These grasps include pen grasp, palm grasp, modified pen grasp, and modified palm grasp. There are two main HVE grasps: thumb-to-nose grasp, and pen grasp. In the thumb-to-nose grasp, the assistant holds the HVE in this grasp for maximum control of the HVE. The hand is wrapped around the HVE, with the thumb pointed toward the patient’s nose. In the pen grasp, the assistant utilizes this grasp primarily for assisting with dental treatment performed in the anterior area of the oral cavity.
Fulcrum is a resting point for the operator’s working hand. A fulcrum allows for stability and control while utilizing an instrument or dental hand piece in the patient’s mouth.
Direct and Indirect Vision
The operator utilizes both direct and indirect vision while performing dental treatment. Direct vision is when the operator has a direct line of sight to the area of the mouth on which she or he is working. Indirect vision is when the operator looks into a mouth mirror to visualize the area of the mouth being worked on. The assistant is responsible for spraying air on the mouth mirror to keep the dentist’s line of vision clear.
Generalized: In a general dental office, one will find a wide variety of dental instrumentation from each specialty. There will be a limited amount of specialized instrumentation, depending on how often the general dentist performs that specialty procedure. Some instrument setups found in a general dental office are basic setup, restorative set-up, crown and bridge setup, and emergency setup.
Specialized: In a specialty office, one will find instruments specific to that specialty. For example, an orthodontic office will have a specific instrument setup for cementation of bands, bonding of brackets, adjustment of arch wire, changing of elastics, and removal of orthodontic appliances.
Hand-Piece Identification and Utilization: High-speed hand pieces are all one unit, spray water, and have a fiber-optic light. They rotate at 450,000 rpm, are used for preparation of teeth for restorations, and are slightly angled. Hand pieces are designed to spray water to wash away debris and to keep the tooth cool and prevent overheating. Slow-speed hand pieces have multiple parts and attachments, with a motor in the base. Attachments include straight, contra-angle, and prophy-angle.
Bur Identification and Utilization: Dental burs are drill bits used in hand pieces. There are two main types of burs—carbide and diamond. The three bur shanks are straight, friction grip, and latch type. The three parts of the bur are the shank, neck, and head. The head of the bur cuts the tooth structure, and comes in many shapes. Burs are inserted into hand pieces to perform dental treatment.
Hand instruments are classified according to their use. Hand-cutting instruments are those used by the dentist to cut actual tooth structure (usually dentin). Hand-carving instruments are used to “carve anatomy” into the restorative material (amalgam). Exploratory instruments, also known as exam instruments, are used to perform an intraoral examination. This set includes the mouth mirror, explorer, cotton forceps, and a periodontal probe. The mouth mirror is used to retract the cheeks, lips, and tongue, as well as to reflect light and provide indirect vision.
Another category of hand instruments are accessory in nature. Crown and bridge scissors, articulating paper holders, and dappen dishes are a few examples. Articulating paper holders secure the colored marking paper used to identify high spots on a newly placed restoration (amalgam, composite, crowns, bridges, dentures, or partials).
Local Anesthetics and Analgesics
All dental assistants must be knowledgeable about anesthetics and analgesics.
The topical anesthetic numbs the gum and nerves to allow the dentist to administer the local anesthetic to the patient with the least irritation or pain. The most common form of topical anesthetic is gel.
The mandibular block injection is placed in the retromolar pad area in order to anesthetize the fifth cranial trigeminal nerve. Because the maxilla is more porous than the bone of the mandible, infiltration anesthesia is used. The operator injects the anesthetic around the area of the root above the target tooth/teeth. A vasoconstrictor is found in some anesthetics in varying ratios (1:20,000; 1:50,000; 1:100,000; and 1:200,000). This chemical gives a deeper anesthesia and lasts longer than plain anesthetics. Caution should be used for medically compromised patients (cardiac or hypertensive patients) with the use of vasoconstrictors. Parasthesia is the prolonged effect of the anesthetic and may be caused by expired anesthetic solution, anesthetic apparatus prepared in advance (metal ions from the needle leach into the solution), or if the nerve is damaged or nicked during the anesthetic process. Parasthesia may be permanent or subside after several days, weeks, or months.
Assembly of Syringe
Dental assistants cannot administer local anesthetics, but they must be knowledgeable about them and be able to prepare the syringe for the dentist. This preparation involves aspirating the syringe, inserting the carpule, engaging the harpoon, selecting the proper size needle, and transfering the syringe to the dentist.
Needle Lengths and Usage
Needles come in two lengths: short or long. Long needles are used for mandibular injections, while short needles are used for maxillary injections.
Carpule labels have a wealth of information: name of the anesthetic, the concentration, expiration date, manufacturer’s name, and so on. The assistant should always double-check the expiration date and color code, and inspect the carpule for signs of damage.
Disassembly of Syringe
To disassemble the syringe, remove the needle, place it in a sharps container, disengage the harpoon, remove the carpule, and dispose of it properly. Remember to sterilize the syringe after use.
Proper Disposal of Sharps
Dispose of all used needles in a sharps container.
Nitrous-oxide sedation is a gas mixture of oxygen and nitrous oxide administered through an inhalation technique. This is generally the responsibility of the dentist. However, in some states, assistants with expanded function credentials may also perform this function. Following the procedure, the patient should be flushed with 100% pure oxygen ten minutes prior to the end of the procedure. The patient should never be left alone while on nitrous oxide. The patient should be awake and responsive. Prior to leaving the office, the patient should be as alert as he or she was on entering the office. Note that the nitrous-oxide and oxygen tanks and gas lines are color coded. Nitrous oxide is blue and oxygen is green. There are hazards associated with exposure to nitrous oxide and it should never be administered to pregnant women or patients with breathing difficulty. A scavenger system is mandatory to protect dental personnel from ambient gases released by the patient upon exhaling.
Dental Support Aides
The rubber dam is utilized for retraction, moisture control, isolation, and patient management. The entire dam system includes the frame, punch, rubber dam material, template, napkins, lubricant, forceps, and clamps.
The dental dam frame holds the material taut and secures it extraorally. The dental dam clamp comes in varying sizes and may be winged or wingless. The clamp secures the dental dam material around the tooth. The dental dam punch makes the holes in the dental dam material that isolate the tooth/teeth. The #1 hole (smallest) is used for mandibular anteriors, #2 for maxillary anteriors, #3 for premolars, #4 for molars, and #5 for bridges or as the anchor tooth. The material between the holes is called the septum. This is cut using crown and bridge scissors when removing the dental dam material after the procedure. The various-sized holes correlate to the different teeth in the arch. One hole is used for endodontic treatment, while 6–8 teeth are recommended for multiple-tooth isolation. The dental dam forcep is used to open and release the clamp in order to place and remove the clamp from the tooth.
Other Moisture-Control Aides
These include dry angles (or dry aids) and cotton rolls.
Tofflemire Retainer with Matrix Band
The main parts of this retainer include the outer nut, inner nut, spindle, diagonal slot vise, and guide channels. It is used to build a temporary wall or matrix to replace lost tooth structure while the filling material is being placed. There are two types of matrix bands: universal and MOD. Other types of matrix systems include automatrix, omni matrix, and palodents.
Other Duties of Dental Assistants
Before dental procedures even begin, the dental assistant must welcome the patient into the operatory and make him or her comfortable. It is customary for the dental assistant to take the patient’s pulse and blood pressure. Normal resting pulse rate is between 60 and 100 beats per minute. Blood pressure consist of two numbers, the higher one being the systolic and the lower the diastolic. Normal blood pressure is considered to be 120 over 80.
Clinical and Periodontal Charting
It is important for the dental team to keep good records, and charting is an essential part of that. Traditional records were kept on paper charts, but today, more and more dental offices are computerizing charts.
Black’s Cavity Classifications
Black’s Cavity Classifications describes the location of the decay on the tooth. It includes six classes according to the location of the cavity. The system also suggests the best way of restoring the tooth. For example, in perio charting, Class II indicates moderate mobility. In orthodontics, patients are screened by their occlusion. Once established, the orthodontist will classify the type of malocclusion according to Angle’s classification. Class I is normal, Class II is distocclusion where the maxillary teeth stick out beyond the mandible in an abnormal degree, giving the appearance of buck teeth. Class III is known as mesiocclusion and the mandible juts out anterior to the maxilla. For example, an occlusion with tongue thrusting is a Class II.
During a composite procedure, the steps of tooth preparation basically mirror that of an amalgam restoration. Once the tooth is prepared with orthophosphoric acid (etchant) and the bonding agent is placed, a clear plastic mylar strip (or celluloid strip) is placed to act as a matrix. The clear matrix allows for operator visibility, as well as for the curing light to polymerize the composite material. The composite will not stick to or become discolored from the mylar material.
Staining of the teeth can come from several sources. Stains are categorized according to their location and source. Extrinsic stains occur on the outside of the tooth structure, while intrinsic stains are integrated into the tooth itself. Exogenous stains occur from sources outside of the tooth (smoking, drinking coffee and colas, etc.). Extrinsic stains are removed during the coronal polishing portion of a dental prophylaxis, or by using bleaching techniques.
Each specialty uses highly specialized instrumentation and procedure setups. There are nine dental specialties, as listed below:
- endodontics—treatment and diseases of the dental pulp
- periodontics—treatment of the diseases of the supporting structures, gingiva, and alveolar bone of the oral cavity
- pediatric dentistry—treatment of children from birth through adolescence
- orthodontics and dentofacial orthopedics—treatment and correction of all forms of malocclusion
- prosthodontics—restoration of oral function by restoring natural teeth or replacing missing teeth with a prosthesis (denture, partial, bridge, or implant)
- oral and maxillofacial surgery—diagnosis and surgical treatment of diseases, injuries, and defects of the oral and maxillofacial regions
- oral and maxillofacial pathology—diagnosis and treatment of abnormalities of the soft tissues and surrounding oral region
- oral and maxillofacial radiology—production and interpretation of X-ray images
- dental public health—promotes dental health in the community; prevents and controls dental diseases via educational means
Oral and maxillofacial surgeons extract teeth, biopsy lesions (abnormalities), correct anatomical defects, and place dental implants, to name a few procedures. For instance, rongeurs are used to contour the alveolar bone to eliminate sharp edges prior to the fabrication of a complete or partial denture. After an extraction, some patients experience alveolitis, also commonly known as a “dry socket.” This occurs due to the loss or lack of development of a healthy blood clot in the alveolar socket. A surgical dressing is placed in the alveolus until adequate healing has occurred.
Pediatric dentists treat children from newborn through adolescence. Older patients with special needs may continue to be treated by the pediatric dentist. Patients with physical or mental disorders can be treated in a hospital under the care of a pediatric dentist with hospital privileges. All others are seen in the pediatric dental office. Aside from the regular dental procedures, pediatric dentists also treat many emergencies seen in children. For instance, traumatic intrusion occurs when a tooth has been forced inward by a fall or sports injury. Avulsion occurs when the tooth is completely knocked out of the alveolar socket.
In the specialty of endodontics, the dentist treats diseases of the pulp and surrounding tissues. Pulpal irritation can be classified as reversible pulpitis or irreversible pulpitis. In reversible pulpitis, the dentist places a sedative medicament over the pulpal floor in order to give the pulp time to heal and calm down. If this works, further treatment is not necessary at this time. Irreversible pulpitis occurs when the pulp becomes infected or dies due to trauma or decay. Root canal therapy is then performed by the dentist unless the patient chooses an extraction.
During the course of a root canal, the dentist cleans out and enlarges the canal(s) of the tooth. This is done using small instruments such as broaches, reamers, and files. Once the chamber is uniform in size and enlarged enough to accept the final filling material, the doctor will irrigate the canal(s) with a mixture of sodium hypochlorite and water. This step will “sterilize” the canal by removing any tissue particles or debris from the small chamber of the canal. The canal is thoroughly dried with paper points prior to the placement of the gutta percha filling material. The gutta percha is cemented into the canal with a sealer cement.