A-Dental Clinic design

Reception area

Administrative area

Treatment area: Dental operatory

Sterilization area Sterilization area

Dental laboratory

Dentists private office

B- clinical equipments

patient dental chairs

Dental unit

Operator and assistant stools

Dental Operating Lights Dental Operating Lights

Dental unit waterlines

Oral evacuation system

compressors

patient dental chairs

stable base and lift mechanism (hydraulic type is quieter than screwstable base and lift mechanism (hydraulic type is quieter than screwdrive type)Seamless and removable upholstery for easy cleaning/repair (allvinyl is recommended, because it can withstand disinfectionprocedures)Adjustable headrest for patient comfort and operator visibilityErgonomic contoured designMovable armrests for easy patient access and wheelchair transfersAuto preset positioning and auto return with safety stopFoot controls or a touch pad to adjust the chair position

Dental unit

Types of dental unit delivery system

1-Over-the-Patient Delivery

2-Rear Delivery

3-Side Delivery3-Side Delivery

Dental unit

1-Over-the-Patient Delivery

Advantages The most ergonomically-

sound system for the dentist

Easily converts to left-handed or right-handedMoves up or down with

Disadvantages The most visible system to

patients in terms of seeing the instruments

Is very confining for patients Patients may bump into unit

if they rise up suddenlyNot generally recommended Moves up or down with

the chair to maintain a constant relationship

Provides the most practical use of space

Allows dentist and assistant to handle instruments and switches

Allows the dentist to release the handpiecewithout looking up

if they rise up suddenly Not generally recommended

for treating children or patients with conditions that result in aggressive behavior or unpredictable movements

Patient's feet can get tangled in the handpiece cords

Dental unit

Advantages Least expensive system and

easily combinable with an assistant cart for little additional expense

Easily converts to left-handed or right-handed

The least-visible system for patients

Disadvantages Ergonomically less sound for

the dentist, who must twist to reach handpieces or instruments

Places the dentist at increased risk for sharps injuries from dental burs, due to the location of the handpiece holder near the dentist's forearm

2-Rear Delivery

patients Easy patient access to dental

chair Allows handpieces to be

transferred and burs to be changed by the assistant

Easy to connect to in-wall utilities

dentist's forearm Cords can become tangled and

difficult to position for efficient use

Requires two entries to operatory--one for the dentist, and one for the assistant

Makes working alone or standing up difficult for the dentist

Dental unit

Advantages

Provides easy patient access to chair

Less confining to patients

Easy to connect to in-wall utilities

Disadvantages

3-Side Delivery

Disadvantages

Most do not convert to left-handed and right-handed

Handpieces inaccessible to assistant, so dentist must change burs

Ergonomically less sound for the dentist, who must twist to reach for handpieces or instruments

Dental Operating Lights

Wall mounted Dental unit

mounted

Ceiling hung

LEDs offer many advantages over traditional halogen

bulbsbulbs

lower energy

longer life 12-25 year life compared to 3-6 months,

brighter than halogen products

No heat in the beam, for dentist &patient comfort.

The cooler temperature also means no premature curing

during restorations, allowing you to provide the highest

quality of care to your patients

A-Compressed Air

Compressed air is used throughout the office to

propel handpieces, dry teeth, clean out hand-

held instruments before sterilization, and to do

lab work. The compressor is most often located lab work. The compressor is most often located

in the dental mechanical room. Supply lines are

typically fabricated of 1/2" copper pipe.

B-Electricity

Electricity powers:1-the chair itself2-chair-mounted accessories like the dental light

and fiber optic lights on the handpieces.and fiber optic lights on the handpieces.3-X-ray equipment, X-ray view boxes, cabinetry,

and smaller instruments and accessories.4-If the dentist has chairside computers, a

dedicated electrical circuit with surgesuppression is usually installed

D-Dental Vacuum

A dental vacuum system ("suction") collects waste gases,liquids, solids, and debris from the mouth. The centralvacuum pump, found in the mechanical room, draws thewaste material into a main trunk line of 1"-2 diameter.Once the waste reaches the treatment room, liquidsdrain into the sanitary sewer system and gases aredrain into the sanitary sewer system and gases areexhausted to the outside of the building.

E-DrainIf a cuspidor is used, a drain line must be provided forwastewater. Drain wastewater flows into the main sewerline.

Dental Handpiece

Low-Speed Handpiece

Speed ranges from 10,000 to 30,000 rotations per

minute (rpm).

Straight in appearance.

Straight attachment receives a long-shank Straight attachment receives a long-shank

laboratory bur

Contra-angle attachment receives latch type

rotary instruments and mandrel.

High-Speed Handpiece

Operates from air pressure.

Operates at speeds up to 450,000 rpm.

Maintains a water-coolant system. Maintains a water-coolant system.

C-Dental Radiology

the kilovoltage range for most

dental x-ray machines: 65 to

100 kV

milliamperage range for dental milliamperage range for dental

radiography:7 to 15 mA

Filter Absorbing material, usually aluminum,placed in the path of the beam of radiation toplaced in the path of the beam of radiation toremove a high percentage of the low energy(longer wavelength) x-rays.. they are addedfiltration, Inherent filtration, and Total filtration.

Collimator A diaphragm, usually lead, designedto restrict the dimensions of the useful beam. toan appropriate size. Intraoral beam diameter iscollimated to 2 3/4 in. (7 cm) at the skin surface.

Types of X-Rays

Intraoral Radiographs

Extraoral Radiographs

Digital RadiographsDigital Radiographs

X-ray Generator - alternating Current(AC) versus

Constant potential (DC):

constant potential units typically operate at 60 or 65 Kv

compared to the 70 kVp of an alternating unit

Constant potential units (DC) produce lowercontrast conventional films compared to AC

Constant potential units (DC) produce lowercontrast conventional films compared to ACunits at any given kVp, but these units typicallyoperate at a slightly lower kV than AC units,which decreases this difference. Constantpotential units may reduce patient exposureslightly and may produce more consistentexposures at the very short exposure timesassociated with digital radiography

Intraoral Radiographs

Periapical X-rays Bite-wing X-ray Occlusal X-ray

Extraoral Radiographs Panoramic X-rays requires a special machine. The

tube head that emits the X-rays circles behind

your head while the film circles across the front.

That way, the full, broad view of the jaws is

captured on one film. Devices attached to the X-

ray machine hold your head and jaw in place. theray machine hold your head and jaw in place. the

process is very safe. It often uses less radiation

than intraoral X-rays.

Cephalometric projectionsare X-rays taken of the

entire side of the head. They are used to look at

the teeth in relation to the jaw and the person's

profile. Orthodontists use cephalometric

projections to determine the best type of

orthodontic treatment.orthodontic treatment.

Cone-beam computed tomography (CBCT)

provides three-dimensional images. You stand or sitwhile the machine rotates around your head. Thebeam is cone-shaped, instead of fan-shaped as in astandard medical CT. It uses less radiation than amedical CT scan but far more than any standarddental X-ray. CBCT is particularly useful for dentalimplant selection and placement.implant selection and placement.

. A major advantage of CT is its ability to imagebone and soft tissue at the same time

Standard computed tomography (CT) usually

must be done in a radiologist's office or a

hospital.The radiation exposure is higher for this

type of CT than for a cone-beam CT. A standard

CT scan may be done to determine size and

placement location for implants.

Digital Radiographs

one of the newest X-ray techniques. Standard X-ray

film is replaced with a flat electronic pad or sensor.

The image goes into a computer, where it can be

viewed on a screen, stored or printed out. Digital X-

rays taken at different times can be compared using arays taken at different times can be compared using a

process that highlights differences between the

images. Tiny changes therefore can be caught earlier.

Used properly, digital X-rays use about half the

radiation of conventional film.

Radiation dose and protection

The dosage of X-ray radiation received by a

dental patient is typically small (around

0.150 mSv for a full mouth series, according to

ADA website), equivalent to a few days' worthADA website), equivalent to a few days' worth

of background environmental radiation

exposure

For pregnant dental personnel, the radiationexposure limit is 0.5 mSv per month.

Individual doses in basic dental radiography (intra-oral, panoramic and cephalometric) are low.

Individual doses from more complex imaging (CTscans and multiple slice cross-sectionaltomography) can be substantially higher

Individual risks in dental radiography are small butare greater in the younger age groups (below 30years)

Protection of Staff

lead apron must always be provided to any person,

whether a member of staff or a family member/member of

the public, who holds or supports a patient during a dental

X-ray.

By ensuring that operators of X-ray units adhere to safe By ensuring that operators of X-ray units adhere to safe

working practices, e.g. by remaining at a distance of at least

2 m from the patients head during exposures and not

standing in the path of the primary beam, they will not be

exposed to any risks from the routine operation of the

units. If the room is too small the operator should stand

behind a protective screen or outside the examination

room.

Sterilization and Disinfection

of Patient Care Items

Critical items

Penetrate soft tissue or contact bone (e.g. all surgical instruments,

periodontal scalers, etc.) Cleaning followed by , sterilization

Semi-critical items

Contact mucous membranes or non-intact skin (e.g. mouth

mirrors amalgam condensers, reusable impression trays,

handpieces, etc.) Cleaning followed by, sterilization*

Non-critical items Contact intact skin, but not mucous

membranes, or do not directly contact the patient (e.g.

radiograph head/cone, blood pressure cuff, facebow, pulse

oximeter, etc. Cleaning followed by low-level disinfection

The instrument processing area

should have clear separation of clean and dirty

areas with separate sections for:

receiving, cleaning and decontamination;

preparation and packaging; preparation and packaging;

sterilization;

storage

Sterilization

Heat-tolerant instruments are usually sterilized by

A-steam under pressure (i.e. autoclaving),

B- Unsaturated chemical vapor

C-dry heat C-dry heat

A-steam under pressure (autoclaving)

There are three types of steam sterilizers based on how

air leaves the unit.

1-gravity displacement (performs type N cycles),

2-vacuum assisted (performs type B cycles)2-vacuum assisted (performs type B cycles)

3- positive steam flush with pressure pulses (performs

type S cycles

B-chemical vapor sterilizers

Unsaturated chemical vapor sterilizers (Harvey

sterilizer or Chemiclave) use a special chemical

solution instead of water to generate a killing

vapor. Operational conditions are 132C/270F vapor. Operational conditions are 132C/270F

with a pressure of 172 kPa/25 psi for 20

minutes.

C-Dry heat sterilization

Involves heating of air and then transferring heat

energy to instruments. The process requires

temperatures higher than steam or unsaturated

chemical vapor sterilizers. Operational chemical vapor sterilizers. Operational

temperatures vary from 160C to 190C

Plasma Low Temperature Sterilization

with Vaporized Hydrogen Peroxide

low temp sterilizer (PlazMax) that

provides an efficient sterilization for heat

& moisture sensitive equipment& moisture sensitive equipment

Management of Contaminated Dental

Unit Waterlines

Dental unit waterlines (DUWL) are colonised by

bacteria derived from the incoming mains water

and to a lesser extent by oral bacteria that enter

the waterlines via suck back through the the waterlines via suck back through the

handpiece

Methods used to reduce biofilm

formation

1-Anti-retraction valves and flushing

Most dental unit waterlines incorporate anti-retractionvalves to prevent back-siphonage up stream into thesurgery plumbingsurgery plumbing

An integral component of airturbine handpieces. Inthe handpieces the valve reduces suck back of fluidsfrom the oral cavity.

Flushing the waterlines for 2 minutes at the start ofthe day and for 20-30 seconds between patientsreduces the bacterial count by approximately 97%