Monthly Archives: September 2015

Cone Beam Computerized Tomography Dental Imaging


CBCT systems used by dental professionals rotate around the patient, capturing data using a cone-shaped X-ray beam. This data is used to reconstruct a three-dimensional (3D) image of the of the patient’s head and neck. CBCT uses more radiation than regular dental teeth x-rays, but still less than 10% of the radiation used in conventional medical CT scan of the same area.

This is the Carestream 9300 Imaging machine we have at the University of Maryland Dental School. I mostly use this to plan dental implant placement.


Dentists use Cone Beam CT imaging for the following:• 3-D observation of overall oral/facial bony characteristics, allowing easier diagnosis and placement of dental implants • Surgical guide fabrication for implant placement • 3-D observation of teeth for endodontic diagnosis and treatment • Diagnosis and treatment of tooth impactions • Identification of inferior alveolar nerve and mental foramen location • Identification of the location of the maxillary sinus • Identification of the presence of odontogenic lesions • Trauma evaluation and treatment • Analysis of temporomandibular joint characteristics leading to diagnosis and treatment • Integration with CAD/CAM devices for fabrication of prosthodontics or orthodontic appliances • Identification for referral of numerous conditions or diseases not normally within the realm of dentistry, but that can be shown on typical cone beam images.



These last 2 pictures show how we use information obtained from the Cone Beam CT to plan placement of dental implants.

Dr Gentry explains how sugar causes cavities and that it’s okay to enjoy a few scrumptious desserts over the holidays.


It is true that sugar does cause cavities, but it’s not the sugar directly. The naturally occurring streptococcus bacteria that live in our mouths consume the sugar, ferment it, and produce acid such as lactic acid. It is these acids that cause teeth demineralization and the formation of cavities. So it is actually the acid from the bacteria in plaque in our mouth that eats the holes in our teeth causing cavities.


Here’s the interesting part, it’s not the total amount of sugar we eat, but the total amount of time the sugar is in contact with our teeth. It is preferable to have a piece of pumpkin pie with a scoop of ice cream for Thanksgiving dessert, than sip on a soda all afternoon. It is better to have a few sugar cookies, or slice of Christmas apple pie, than to repeatedly sip coffee with sugar all morning long. One Altoids mint or cough drop per hour throughout the day is ten times more cavity producing than 1 big piece of cake for dessert, even though the cake has much more sugar and calories.

The repeated cycles of eating sugar and acid formation is what is the key. It is the frequency, or the amount of time the sugar is in the mouth, not the total amount of sugar. So do enjoy a few scrumptious (and quick) holiday desserts, just please make sure to brush and floss after every meal and visit your dentist regularly. Happy Holidays!!!

Philip A. Gentry, DDS, FAGD

Article published in The Elm, The University of Maryland