High efficiency in the treatment room hinges around accessible work surfaces, locations for dynamic instrumentation like handpieces, syringes and vacuum components and materials storage.  In the general dental office and many specialty practices, the dental assistant typically faces the 12 o’clock area of the operatory when seated. Consequently, cabinetry in that location of the operatory becomes extremely important.

There are three key areas to focus your attention on when considering cabinetry for the 12 o’clock location of your treatment room:  Cabinetry dimensions, design, and construction quality.

Cabinetry Dimensions

If you are developing a new dental facility, you will probably have flexibility in your treatment room dimensions. If you are remodeling an existing office or simply replacing some operatory cabinets, you’ll be more constrained with limited alternatives. Key dimensions to keep in mind that will impact your 12 o’clock cabinet decision include:

  • A minimum of 27” between the headrest of the dental chair when the chair is reclined and the headrest fully retracted and the face of the 12 o’clock cabinet. Any dimension less than this will make it difficult for the dentist to move into a 12 o’clock position and will place the oral cavity too far in front of the assistant when seated with knees toward 12 o’clock
  • A maximum of 32” between the headrest and the face of the 12 o’clock cabinet. Greater distances will make it difficult for the dentist to reach the 12 o’clock work surface when seated in the 9 or 10 o’clock location (3 o’clock or 2 o’clock for lefties) and for the assistant to reach work surfaces and storage areas.
  • A minimum of 14” of space between the toe of the chair and the 6 o’clock wall. This space allows for chair mounted, left / right style operatory lights and handpiece delivery systems  to rotate past the toe of the chair. 
  • At least one entryway with a minimum of 32” of space between the side wall or side cabinet corner and the 12 o’clock wall or cabinet to comply with A.D.A. wheelchair access requirements

With these dimensions in mind, if you are re-equipping an existing treatment room the size of your room will determine how deep and wide the 12 o’clock cabinet can be. If you are designing a new office, you can adjust the treatment room size to accommodate the cabinets of your choice.

Width:  The width of 12 o’clock cabinets built by the leading dental equipment manufacturers varies considerably to accommodate different installation situations. 42” is generally considered to be a maximum for installation in a double entry treatment room where the entry for the doctor, assistant and patient is from the 12 o’clock end of the room. You will also find cabinets as narrow as 30” to accommodate narrow operatories. Wider is usually better, simply because the additional width provides more work surface, more storage space for instruments, materials and ancillary and computer equipment, and more room for the handpiece delivery system when mounted at the 12 0’clock position.

Depth: 12 o’clock cabinets typically vary in depth from 27” to 12”. As with width, the deeper cabinets simply provide more room for work surfaces and storage of instruments, materials, computers, monitors, and keyboard and mouse. Your selection may be dictated by how deep your existing operatory is or can be. For example, using the guidelines above, if you choose a 27” deep 12 o’clock cabinet, your operatory will need to be a minimum of 11’10” deep:

Cabinet depth of 27”, PLUS Minimum space between cabinet and chair headrest of 27”, PLUS Typical chair length of 74”, PLUS Minimum space between chair toe and 6 o’clock wall 14” = 11’10”

If the 12 o’clock cabinet is only 12” deep, the treatment room could be 10’7” deep without compromising the proper ergonomic dimensions.

That said, it is not uncommon to see 14” deep 12 o’clock cabinets installed in 10’ deep treatment rooms. How is this done? With some compromises! For example:

Cabinet depth of 14”, PLUS A compromise in the minimum space between cabinet and chair headrest of 25”, PLUS Typical chair length of 74”, PLUS A compromise in minimum space between chair toe and 6 o’clock wall of 7” = 10’

Countertop height: Since treatment room countertops are used when standing and when seated, the height  should be around 32". This is a compromise between the ideal seated worksurface height of 27" to 28" and ideal standing worksurface height of 36". 



Before you select a 12 o’clock cabinet, do a thorough assessment of your needs. Will you be storing flat trays in the cabinet or are you using instrument cassettes? Will you be using tubs for materials storage or simply using drawers? What ancillary equipment will you be using, such as a triturator, laser, endodontic equipment, intraoral camera, communication system and computer equipment. Where to you want to store these products? Where do you want to locate your handpiece delivery system and vacuum instrumentation? What electrical, air, vacuum and water utilities they require? Answers to these questions will help determine if the design of the cabinet you are considering will meet your requirements.

Construction Quality

The cabinets in the treatment room certainly take abuse and need to be engineered for installation of heavy movable assistants’ work surfaces and 12 o’clock handpiece delivery systems. It is paramount that the materials and workmanship is top notch if you expect the cabinets to hold up over time. Metal sub-base are found on most of top quality cabinets from the major dental equipment manufacturers, eliminating the problem of water damage often found on cabinets that use wood sub-bases. All wood panels should be sealed on the faces and edges to reduce the effect of moisture. To prevent laminate chipping, the use of 3mm PVC edge banding on doors and drawers is important as well. A local custom cabinet maker can design a 12 o’clock to your design specifications, but often do not have the resources, equipment or facility to use metal sub-bases or PVC edge banding and structural steel for mounting of movable work surfaces in their cabinets. 

Also see the article in  "Buyers Advice: Cabinetry" for information on comparing costs of factory built cabinets with cabinets from the local cabinet maker. 


This Buyers Advice article was authored by David Anderson, the President of Voice Market Research. For more information , see “About Us”  


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