McNamara Analysis

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San Francisco native James A. McNamara Jr. is most widely known for his development of the McNamara Analysis, one of the most popular methods of cephalometric analyses. Circa 1983, McNamara’s research focused mainly on clinical modification of the growth of face and jaw.

He introduced this cephalometric analysis because there was a need for a method of cephalometric analysis that is sensitive to not only the position of one’s teeth within a given bone, but also to the relationship of one’s jaw elements and cranial base structures and how they relate to one another. Since, the McNamara analysis has become one of the most important tools of clinical and research orthodontics.

This analysis is one of the more recent additions to the contemporary textbooks on cephalometry. The textbook contains a list of the most well known cephalometric analyses including 23 analyses between the years 1946 and 1985 i.e. Wits Analysis, and Rickett’s Analysis. The majority of these analyses use references from small samples of Caucasians.

The McNamara analysis combines the anterior reference plane, the plane that runs perpendicularly to the Frankfurt horizontal through the nasion) with a description of the length of the patient’s jaw and the relationship between them. McNamara’s approach is the most suitable for diagnosis, treatment planning, and treatment evaluation. This goes for patients with skeletal discrepancies who may be candidates for dentofacial orthopedics and orthognathic surgery.

McNamara Analysis Advantages

The McNamara analysis relates several variables: teeth to teeth; teeth to jaws; each jaw to the other; and jaws to the cranial base. The analysis is a combination of elements of the Ricketts and Harvold approaches, using original measurements to create a more precise definition of jaw and tooth positions. According to this method, the anatomic Frankfort plane as well as the basion-nasion line are used as reference planes.

There are three main advantages of the McNamara analysis. Firstly it depends largely on linear measurements rather than angles. It analyzes the interarch relationship in the vertical plane as well as sagittal making them into one single integrated unit. Lastly, it helps to diagnose external conditions in the airway.

Skeletal Study

According to McNamara, the skeletal and dental components of the face are composed of the following planes and measurements used for skeletal study: Nasion perpendiculars (aka McNamara’s Vertical), linear distance from point A to nasion perpendicular, linear distance from point pog to nasion perpendicular, maxillary length, mandibular length, and lower anterior facial height. The planes and measurements used for the analysis of the airways are upper pharynx diameter and the lower pharynx diameter.

Analysis of Airways

The upper pharyngeal width is the smallest distance from the posterior pharyngeal wall to anterior half of the small plate outline. The normal for an adult is 17 +/- 4. The measurement marked with a decrease is only used as an indicator for possible upper airway impairment. For a more accurate diagnosis you’ll have to see a clinical otorhinolaryngologist for a clinical exam.

The lower pharyngeal width is measured on the mandibular plane from the posterior tongue to posterior pharyngeal wall. The norm for an adult women is 11.3 +/- 4, while the norm for an adult male is 13.5 +/- 4. Values that are less than 15 millimeters suggest that the anterior positioning of the tongue is either postural or there’s an enlargement of the tonsils.

All of these components and measurements can be easily recorded and stored through CephX’s cloud based platform for cephalometric analyses. In cephalometrics, the landmarks, or points of measurement, often demonstrate the relationship of the maxillary teeth and mandibular teeth, the jaws to the teeth and the jaws to one another, and the jaws to the cranial base. By drawing a complex series of angle and plane values, doctors are able to create values to compare for each measurement series.

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CBCT Analysis & Orthodontic Records

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The orthodontic records appointment is your very first step toward a patient’s orthodontic treatment. The orthodontic record is an evaluation tool that is used by orthodontists to determine the treatment needs of the patient. These records aid the orthodontists to provide the most optimal treatment plan, making this a very important step in the process.

This process provides the orthodontists with all of the necessary information, and even more. Often times this information is not evident by the visual examination alone. Therefore it’s important to document the patient’s orthodontic problem to help determine the most appropriate treatment. These records also serve then as a means to determine progress through the treatment and post treatment to evaluate the outcome and decide what further treatment or precautions are necessary.

Before the orthodontist begins planning a proposed treatment plan these orthodontic records must be completed thoroughly. The orthodontist will study these records and determine exactly how the patient’s jaw bones and teeth are positioned and customize a unique treatment plan for each individual case. Below, you will find an extensive list of all of the factors that make up your orthodontic records:

Dental Impressions

Sometimes also referred to as alginate impressions, these guys are used to give the orthodontist an exact duplicate of a patient’s mouth. The model of the mouth is made through a process of pouring stone into an impression mold. The orthodontist uses this model to study the current positioning of a patient’s teeth and can thereby predict the relationship between the upper and lower teeth in the future.

Today, a more technologically advanced solution has emerged to enable orthodontists to obtain 3D images of a patient’s teeth and bite via a digital scanning process, digital impressions. Using a capture wand, and moving it slowly around the teeth it’s able to capture images from all angles of the teeth. Once plugged into the software, the images are stitched together to form a digital model of the patient’s mouth. This eliminates the need for the aforementioned physical impression.

Panoramic X-ray

The panoramic x-ray is a 2D display of both the upper and lower jaws and teeth shown on the same film. This type of x-ray is important for patients in their adolescence, because the dentist can easily view their developing teeth and use that to predict where they will break through in the mouth. Adult patients undergoing or considering orthodontic treatment may also have this x-ray taken in order to examine current health and level of the jaw bone.

Cone Beam CT

Yet another new technology in orthodontic imaging is the CBCT. This exam provides much more in-depth and reliable information that can be useful in orthodontic treatment and diagnosis. When using the CBCT the orthodontist is provided with a 3D view of the patient’s teeth and jaws to help and see more spatial information. This can be especially important in the case patients with a cleft palate or patients with impacted teeth. The CBCT can provide many different views for the orthodontist i.e. standard panoramic and cephalometric views.

Cephalometric Analyses

The cephalometric x-ray captures the patient from their side profile, this begins from the top of their head until just below the tip of the chin. In the cephalometric analyses is a valuable exam because it not only shows the teeth and the bone, but it also includes soft tissues which can help the orthodontist predict how the bone will structure, and its potential to change during orthodontic treatment.

While dentists and orthodontists used to use tracing paper and trace the ceph using key landmarks on the x-ray, yet again new technologies have come along to improve the accuracy and ease orthodontists. With programs like CephX, you can upload your ceph images into the cloud and with RTS (remote tracing services) within 2 business days your traces will be printable, editable, and viewable from the cloud. One of the greatest advantages of working in the cloud, is keeping track of a patient’s progress for legal reasons. If a patient claims they’ve been harmed by your practice, CephX can provide proof through their image storage anywhere and at anytime.

Once the orthodontist has received all of the completed exams and records, all of the potential treatment options are recorded into the patient’s file. Then an additional consultation with the patient is in order to discuss the potential treatment options. During this consultation a final treatment option is to be agreed upon and necessary appointments can be scheduled to begin treatment.

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Orthodontic Treatment Plan

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After your primary introductory appointment with your orthodontist, you’ll be invited back again for a formal evaluation to determine the appropriate course of treatment for your individual case. While some forms of orthodontic treatment may be discussed in the initial appointment, the official plan can’t be finalized until all of the information and tests have been evaluated and reviewed extensively.

For this reason, the consultation is only scheduled upon a few weeks following that initial appointment. During this time the orthodontist has time to receive the models from the lab and prepare the proper treatment plan. In the initial appointment the orthodontic examination will examine the patient’s jaw alignment and teeth. The orthodontist will then collect a set of orthodontic records, i.e. plaster or virtual image models, x rays, and medical dental history.

Orthodontic Treatment Plan – What to Expect

The patient should expect to spend about a half an hour at the orthodontic practice and this session will include a discussion of the diagnosis, the affirmative treatment plan, alternative treatment plans and the possibility for risks and complications. Since the patient should have seen their dental practitioner before arriving to the orthodontist clinic for treatment, this routine check up should prepare them for this discussion. The end of this discussion should include informed consent and a brief analysis of the financial arrangements that will need to take place.

It’s important that if the patient is a minor there’s a parent or legal guardian present for this consultation, as many of the matters being discussed involve legal issues and in addition a parent or legal guardian knows the patient best. This can help the orthodontist to make decisions about proposed treatment options and risks to make sure the best option and treatment method is selected.

For the diagnosis itself you should typically expect the problems regarding bite, spaces, crowding, missing teeth, misalignment, jaw position, or other growth concerns. It’s important that the orthodontist discusses this with the patient and their guardian in depth referencing dental images, x-rays, etc. from the initial appointment.

The Treatment Plan

The specific treatment plan is designed just to address the issues that were covered in the discussion of the diagnosis. The specific appliances and treatment recommendations, i.e. the length of the treatment and the precautions, etc. and the need for cooperation by the patient are also discussed along with the alternative treatment options (even non-treatment).

It’s essential before making a final and somewhat permanent decision that the patient and the orthodontist are aware of all of the different options before deciding on the treatment course. While there may be many advantages and disadvantages to each individual option, a thorough analysis will help in the decision making process. The options will vary amongst different scenarios and situations. Some patients may have a plethora of different options, where others have just one, treatment vs. no treatment.

Finally, at the end of the consultation appointment you’ll receive a contract that provides you with all of the payment information regarding the treatment. The fee will be discussed and signed upon agreement by both the patient and their parent or legal guardian.

Changes in Actions

As we know in life, not everything always goes as planned. Often times there are instances when you or your orthodontist needs to change the course of the treatment plan for a variety of reasons. These could consist of poor patient cooperation, change in growth, patient’s desires, periodontal problems, or improved appliances/technology.

The alternatives in these particular situations may vary in each case of the individual’s specific reasoning, problem, and solutions available. These changes have the capacity to lengthen your treatment time, and could incur additional fees.

All in all, if you maintain good terms with your orthodontist throughout the treatment, and the treatment planning process, you can ensure a pleasant experience and when or if the changes do occur you’ll know you’re in good hands. When using a cloud based system like CephX, changes can be monitored in the patient’s oral health easily and conveniently so the orthodontist is trusted to perform accordingly to see the best results.


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