matrices

What is the primary purpose of dental matrices?

To replace missing walls of a tooth, provide contours during restoration, and prevent interproximal overhangs.

What are the two types of matrices mentioned for posterior restorations?

Tofflemire Matrix and Automatrix.

What is the function of the Tofflemire Matrix?

It is a straight retainer used for buccal placement and can also be positioned contra-angled for lingual placement.

What is the advantage of using a clear plastic matrix for anterior restorations?

It allows curing light to reach the material and protects adjacent teeth during etching and bonding.

What is a T-Band matrix used for?

It is primarily used for pediatric dentistry and does not contour as well as the Tofflemire matrix.

How is the Tofflemire retainer positioned during placement?

The diagonal slot is positioned toward the gingiva, and the handle extends out of the mouth.

What is the purpose of wedges in matrix systems?

They hold the band securely in place, adapt it to the gingival contour, prevent overhangs, and ensure good contact when the band is removed.

What types of wedges are used with dental matrices?

Wooden wedges are used with amalgams, while plastic wedges are used with composites or amalgams.

What is a sectional matrix system used for?

It is used on Class II composite restorations to restore anatomical contacts.

What is the design feature of a matrix band?

When the ends are brought together, the band forms a circle with one side smaller than the other.

What is the significance of the smaller circumference of the matrix band?

It is always positioned toward the gingiva.

What is the purpose of the tension ring in a sectional matrix system?

It creates a solid closure of the cavity preparation by being placed between the band and the wedge.

What is the legal scope of practice for dental assistants in Arizona regarding matrix placement?

Dental assistants in Arizona are legally allowed to place and remove matrices.

What happens if a matrix band becomes creased during assembly?

It can be smoothed by placing the handle of a mouth mirror inside the loop and running it around, a process known as ironing the band.

What is the typical extension of the matrix band below the gingival margin during placement?

The band extends approximately 1.5 mm below the gingival margin.

What is the typical extension of the matrix band above the occlusal surface during placement?

The band extends approximately 2.0 mm above the occlusal surface.

What is the purpose of the clear plastic matrix in anterior restorations?

It protects adjacent teeth from etching and bonding materials while allowing light to cure the restoration.

What is the role of the diagonal slot on the Tofflemire retainer?

It is always positioned toward the gingiva to ensure proper placement.

What is the primary difference between a universal band and an extension band?

A universal band is selected for class II preparations with intact cusps, while an extension band is for deeper preparations requiring gingival extensions.

What is the function of the contoured matrix band in a sectional matrix system?

It is placed interproximally to restore anatomical contacts.

What are the criteria for effective isolation techniques in dentistry?

Easy to apply, protective of soft and hard tissues, comfortable for the patient, provides better visualization, prevents moisture contamination, isolates the area of concern.

What are the advantages of cotton roll isolation?

Easy application, no additional equipment required, flexible for different areas of the mouth.

What are the disadvantages of cotton roll isolation?

Does not provide complete isolation, does not protect from aspiration, may stick to oral mucosa, must be frequently replaced, limited retraction.

What is the purpose of cotton roll holders?

To hold multiple cotton rolls securely in the mandibular quadrant, allowing for better isolation.

What is Dry-Angle isolation used for?

To isolate posterior areas in the maxillary and mandibular arches by blocking saliva flow over Stensen's duct.

What are some other isolation methods besides cotton rolls and dry-angle pads?

Mr Thirsty, Ez Dam, VacuLux.

What is a dental dam?

A thin, stretchable latex material that acts as a barrier, isolating selected teeth during procedures.

What are the indications for using a dental dam?

Infection control, protection from inhalation or swallowing debris, moisture control, improved access, visibility, and team efficiency.

What types of dental dam material are available?

Latex or latex-free, in two sizes (6×6 inches for adults, 5×5 inches for children), various colors, and three thicknesses (thin, medium, heavy).

What is the function of a dental dam frame?

To stabilize and stretch the dam tightly around the teeth, keeping it out of the operator's way.

What is the purpose of a dental dam napkin?

To increase patient comfort by absorbing moisture and protecting the face from direct contact with the dam.

What types of lubricants are used with dental dams?

One lubricant for the patient's lips (zinc oxide ointment or petroleum jelly) and a water-soluble lubricant on the underside of the dam.

What is the function of a dental dam punch?

To create holes in the dental dam for exposing the teeth to be isolated.

What is the purpose of a dental dam stamp and template?

To mark the dental dam with predetermined markings for proper alignment of teeth.

What are dental dam forceps used for?

For the placement and removal of the dental dam clamp.

What are the parts of a dental dam clamp?

Bow (rounded portion), jaws (prongs that seat around the tooth), and holes for forceps placement.

How should a dental dam clamp be positioned?

On the cervical area of the tooth below the height of contour, with the bow on the distal aspect.

What is the purpose of ligatures on clamps?

To retrieve a clamp if it becomes dislodged and is at risk of being inhaled or swallowed.

What is a dental dam stabilizing cord?

A disposable latex cord used as an alternative to clamps for securing the dental dam.

What are the two methods for dental dam placement?

One-step method (dam and clamp placed together) and two-step method (clamp placed first, then dam).

What special applications might require a dental dam?

Restoring anterior teeth or fixed bridges, where specific clamps may be needed for better exposure.

What is the septum in dental dam usage?

The area between holes of the dam.

How can you ensure the septum of the dam passes through contacts?

Use double floss or loop back through contacts.

What should be done to check dental dam placement?

Double check with a mouth mirror and ensure patient comfort.

Is it legal for dental assistants to place and remove dental dams?

The answer may vary by jurisdiction; check local regulations.