8th APO General Meeting

In place of the 8th general APO meeting, members were encouraged to attend two lectures last May 29, 2016 at the 107th PDA Annual Convention held at the SMX Mall of Asia in Pasay City. The earlier lecture (Non-surgical Management of Vertical Discrepancies in Orthodontics) was by APO’s own President Elect, Dr. Martin Reyes. It focused on two types of vertical discrepancies, open bite and deep bite, and dealt with its classification, diagnosis and management. The later lecture (The Age of Digital Imaging in our dental practice) given by Dr. Jean Galindez was a basic introductory piece about Cone Beam Computed Tomography (CBCT).

The topic on vertical discrepancies gathered a sizeable audience and a number of APO members showed up to lend their support. Before the lecture, the attendees were asked to come up on stage. A shy group of people shuffled onto the platform for what was in store — a souvenir picture!

When everyone settled back down, Dr. Martin shared that the short exercise was intended to improve blood circulation to the brain and thus boost one’s concentration and mental focus. One may ask, did it? As an observer, the discussion was well received. Dr. Martin’s charm and sharp wit might have influenced and earned our audience’s attention as well.

Dr. Martin began by showing one of his earlier cases, a deep bite that had relapsed many years later. He advised the audience to look at cases such as this in a positive way repeating the statement, there is no better teacher than doing something yourself. Further, he cautioned on misdiagnosing malocclusion in a single dimension. To aid his listeners, he reintroduced his use of the Venn diagram from Ackermann and Proffit‘s classification system and stressed the issue of having proper records and doing thorough functional and radiographic assessments. The importance being that a correct diagnosis leads to a simpler management.

Anterior open bites were classified into three: myofuctional, dental and skeletal. He explained myofunctional open bites further, as a childhood condition associated with habits (eg. incorrect swallowing) and improper tongue size and/or posture. In children, management means restoring balance of the muscles by controlling the habit through verbal and or physical discouragement and/or orthodontic appliances. While in adults, management means restoring oral health by keeping contacts in a good position, fixing occlusion and speech and tongue posture therapy. In skeletal anterior crossbite and open bite cases, management include removing all 3rd molars, leveling and aligning teeth and correcting the bite through camouflage or the MEAW technique. Mechanics include intrusion of molars and some extrusion of anteriors. Specific methods shown in cases are the use of gummetal wires with anterior box elastics, strategic bracket positions, extraction of 2nd molars when 3rds are properly aligned and alignment of the curve of spee where a posterior open bite was present.

He opened his 2nd topic with a case that showed a child with a deep bite during her primary dentition. Revealing the child as his own, Dr Martin confessed that he “experimented” with her case by using only an orthodontic appliance to raise her bite. With much dedication on his part, and several “hidden” treatments from his wife, his child, many years later, is seen with a vastly improved and corrected permanent bite. In spite of this case’s simplicity, it was emphasized that anterior deep bites are tricky to treat due to the high degree of relapse and an often unseen skeletal component. In the mixed dentition, preliminary correction is approached by intrusion of anterior teeth, extrusion of molars and rotation of the mandible. In the late mixed and early permanent dentition, the vertical dimension is raised for better mandibular posture, with strategic bracket positions, and a combination of incisor intrusion and molar extrusion. Specific methods shown in cases are the use of gummetal in an intrusion arch, strategic bracket positions and the use of a Nance appliance with a bite ramp among others.

The last topic explained were the features of a posterior collapsed bite. These cases often have compromised posterior occlusion, periodontal conditions, cosmetic challenges and TMD symptoms. For uprighting tilted molars with deep pockets, management involve the use of TADs (temporary anchorage devices) with light forces or in some cases, occlusal recontouring. Management of cases with TMD symptoms, include using a NTI appliance (anterior bite stop) to relieve masticatory forces or a flat diagnostic splint to restore vertical dimension.

To end, Dr. Martin invited his audience to attend the 10th Biennial National Orthodontic Congress this August. Several showed their interest to attend and a number consulted with him after the lecture. I couldn’t be more proud of our amicable president elect dutifully sharing his time and wisdom that day.

Two rooms down and an hour and a half later, Dr. Galindez gave a short discussion on CBCT terms, advantages and orthodontic applications. Her lecture benefited dentists looking to invest in and or attempting to incorporate and clinically apply a CBCT in one’s practice. At the start, she pointed the importance of understanding the basic terms used when discussing CBCTs such as voxel (versus pixel), dicom (versus jpeg/png) etc. by comparing these to that of a SLR camera. She advised knowing these so one is not lost during discussions or product presentations. From here, the talk continued on the different FOVs (field of vision) a CBCT can have when it takes a scan. She explained that depending on the anatomy you need to see, a CBCT unit can have a large (maxillofacial region), medium (dentoalveolar region) or small (localized to1-2 teeth) FOV.

A pressing concern discussed when taking a CBCT scan is the amount of radiation involved, measured in Sieverts (Sv). Sv is a derived unit of ionizing radiation dose in the International System of Units (SI) that measures the health effects of low levels of ionizing radiation on the human body. It was insinuated that while a normal panoramic scan usually gives off around 32 Sv (Sievert), CBCTs may give off as little as 19 to as much as 1073 Sv. The amount of Sv is related to the amount of time one is exposed to the scan, and associated with the imaging detector, field of view (FOV), and voxel sizes used. As a general precaution, Dr. Galindez advised the audience to always check the list of safety doses.

While the amount of radiation may be an advantage or not, a great advantage over conventional film is a CBCT’s image manipulation. Since the multiplanar image can be seen from a coronal, sagittal and axial view, one is able to select the information (image) of greatest diagnostic value. CBCT manufacturers also provide manageable software programs to guide its use. Other advantages of using a CBCT include the following: Contrast Enhancements to effectively compensate for an over or under exposed image; An Interactive display mode that can be applied to maxillofacial imaging; and 3D reconstructions of intra and extra oral images used when doing root canals and visualizing facial fractures in all 3 dimensions; In the field of orthodontics, the CBCT’s value depends mostly on its software application. These applications include 3D cephalometric analysis, superimpositions of soft to hard tissue and image filtration for clarification of soft tissue profiles. The digital images can easily be stored cheaply indefinitely and can be communicated quickly without damage. This technology is also environmentally friendly since plates and sensors are reused and processing chemicals are not. But like all good things, they always come with some disadvantages. These are its high cost, the varied sensor dimensions it can come with, cross-infection control from reuse of and a number of medico-legal issues.

Dra Galindez’s humorous stories on her personal experiences using a CBCT (or not) dominated most of the talk till the end. To those who are planning to purchase such technology, Dr Galindez suggested to attend several product presentations of available systems in the country to see which system will benefit one the most. Unfortunately, the workshop scheduled after the lecture was cancelled due to time constraints.

The end of the two lectures placed an end to the “8th general meeting”. While several members still ventured into the trade hall, most decided to call it a day. It was a Sunday after all, and tomorrow would be another workday for most.