When a patient has periodontitis, they suffer from a destructive inflammatory infection that significantly impacts their oral health and damages their periodontal structures. Understanding how occlusion impacts or worsens this damage is key to helping these patients prevent unnecessary trauma.

Periodontitis and Occlusal Trauma

Even before the 1960s, there was research linking occlusal trauma and progression of periodontal disease. More recent research has found that this link isn’t as strong as once thought. Still, a relationship has been identified between the extent of damage and whether the patient has an occlusal interference.

One crucial aspect of periodontitis is that it is unique to every patient. This means we have to be careful not to apply a blanket approach to all patients or rely too heavily on past data that may not help us treat our current patient. Their individual susceptibility to periodontitis must be assessed based on their distinct risk factors.

The Relationship Between Occlusion and The Periodontium

For each tooth, occlusal experience matters and may be one of the reasons that loss of attachment worsens. A 2001 study by Harrel and Nunn found that there was a correlation between amount of periodontal damage and existence of occlusal interference. Perhaps more interesting, they also found that changing the occlusion had a positive impact on the periodontal issue.

Even in light of this research, the relationship between occlusion and periodontium is hotly contested. Regardless of one’s opinion on this matter, there’s no denying that the periodontium is effected by occlusal force. When there is no occlusal loading, there may be over-eruption or drifting of the tooth. On the other hand, when the force is appropriate, the periodontium is healthy and stable.

We must remember that there is a spectrum of susceptibility to periodontitis. For those who are very susceptible and also have teeth experiencing occlusal trauma, the latter only serves to worsen the situation.

Current digital splint technology requires workarounds to make it a feasible option for clinically exceptional dentistry. In Part 1 of this series, I described the challenges and opportunities of digital dental technology and explained some details of my preferred protocol. Here, I continue this explanation:

An Effective Digital Splints Protocol

In my practice, I mount digitally printed models using a centric relation record and a protrusive record for condylar inclination adjustments. This is just like we have done in the past with stone models. 

The lab technician can transfer this into the computer exactly as we have it in our hands. They do this with the use of a tabletop scanner. It’s important to note that the technician can now register original files for the impressions into position for the best accuracy. The greatest benefit today is the accuracy of these original scans (20-30 microns). 

The design portion comes next in this process. Communication with the technician can be done in real time online. My technician and I have been working with different settings in the software that give me the best chance of skipping the reline procedure patients don’t enjoy. 

I can also evaluate and do final adjustments on the mounted digital models and analog articulator. We have been successful about 80% of the time getting a splint that is rock solid and has an intimate fit on the occlusal surfaces. This is critical for fine-tuning adjustments and fracture resistance. 

If it ends up as an ill-fitting or loose-fitting splint, we can still reline just like we always have because it is a milled PMMA material (as dense as a denture tooth). 

Areas of Improvement for Digital Splints

My opinion at this time on digital splints is mixed:

Pro: We can produce a very high quality PMMA splint that lasts longer and generally gives the patient a better experience.

Con: We still need digital counterparts to essential analog skills that provide for all situations. 

Pro: I believe we will have printed materials that outperform current milled materials in the near future (this will lower the cost to produce splints). 

Con: It is frustrating that we are not getting better support from companies selling us  expensive equipment.

I am proud to be part of the Pankey family because our community encourages the use of technology to enhance good dentistry. 

The new challenge facing us in dentistry is how to incorporate technology into our daily practice. Digital splints specifically are a subject I have been working on for about a year. 

We have had the technology available to mill a splint out of acrylic for a few years now. However, we have not had a good protocol that meets all our needs. 

Digital Splints: Challenges

Some of the problems we face are as follows:

1) Lack of digital articulators that make all of the movements we are able to with semi adjustable articulators, such as crossover transitions. 

2) Absence of centric relation record mountings in software on a computer.

3) No rotational path insertion we can achieve from relines in the mouth. 

4) Few materials that are as good or better than we have now.

I believe we are well on our way to solving these issues. The biggest problem I see is something Dr. Pankey was dealing with many years ago. He talked about how the majority of dentists are indifferent to good comprehensive care dentistry. Therefore, most of the manufacturers of our dental equipment and software are catering to a majority that does not share our own clinical demands. 

These companies give me answers like, “That sounds great doc but who will I be able to sell that to?” I think we have to find workarounds for now that will encourage development in these technologies. Keep in mind, all of the workarounds I will explain are in line with what we teach at the Pankey Institute. 

Digital Splints: Opportunities

We also need systems we can duplicate and teach without compromising the quality of care or experience for patients. I believe there is great potential for higher quality materials and great fitting splints without relines. These two potentials alone can create more value and better experiences for patients.

Today I have a protocol that is some digital and some analog. I intraoral scan our impressions with the TRIOS scanner. I believe most of the scanners on the market today work very well and produce very accurate files that can be printed into models. I also use the TRIOS because it communicates very well with the 3SHAPE units most labs use. 

Now that I have files and models I have to mount them. This is our first problem to solve. I still use an analog facebow or facial analyzer. I mount these models on an articulator like the Denar Mark 330 because this is an articulator model programmed into the 3SHAPE software. 

To be continued…

How do you ensure aspects like pitch, bevel, crossover, and trailing edges are taken into account? Here, Dr. Green continues his commentary on this valuable aspect of dentistry.

A Flaw of Design: Why Leading & Trailing Edges Matter

While I was helping in the Pankey Scholar Program, the participants would video their patient during the post-case conversation. They would record the movements of the patient in protrusive, left, right radial lateral into crossover, and lateral protrusive.

As I was observing patients in the videos, I would occasionally notice a hesitation once they got to the tips of the cuspid. Sometimes there would also be a quiver of the jaw or muscle twitch. I would usually review the video later with the participant and look at the finished case on the articulator with them. We would talk about how they could put a ‘landing facet’ on cuspids too since they are anterior teeth.

They were beautiful porcelain cases, so I would show them on another set of models how easy it was to do. I told them they would know it was right when the patient’s eyes smiled and the hesitation and muscle twitching went away. Another benefit of a facet on a cuspid is that it is gentler on opposing incisal edges of centrals and laterals in all mandibular movements.

Talking About Edges

One way to talk about the leading and trailing edges: on upper anterior teeth, including cuspids, the leading bevel is at the lingual-incisal junction. The bevel develops naturally on natural teeth. With restorations, the dentist creates it.

The leading edge of the lower incisors, including cuspids, is on the facial incisal junction. It is created in natural teeth with normal function. When restorative material is used, it must be managed by the dentist.

The trailing edges and bevels (labial-incisal edge of upper anteriors plus cuspid and lingual-incisal edges of lower anteriors, including cuspids) are always shaping with function. This can lead to micro-fracturing or major sheering of enamel vertically. Therefore, the trailing edge bevel must always be managed by the dentist with intention. The goal should be preventive with natural tooth or any restorative material.

Once a natural tooth has been worn to the point of losing incisal embrasure, the medial and lingual marginal ridge convex Shaw on the lower can act like a chisel against the labial incisal edge of the upper. This is seen often in a crossover position.

Edges, bevels, and pitch may not be simple, but awareness comes in the doing and observing!

When Dr. Richard Green read Dr. Lee Ann Brady’s blogs on pitch and bevels, he decided to jump in with a thoughtful response. Read on for more discussion of this fascinating topic.

Crossover and Movement: Consider the Edges

I loved Dr. Brady’s article concerning edges (pitch and both bevels) and the conversation about natural teeth, composition, and porcelain. I was reminded of some of my learning with and from Henry Tanner while refining my occlusion in the mid-70s. It worked for me no matter what material and bite splints were used.

Henry was the first to introduce me to ‘crossover.’ At the time, one of the anterior teeth you did not talk about were the cuspids. They too have important facets (pitch and two bevels) that need to match cusp tip to cusp tip, regardless of the material.

When moving into crossover and the cuspid tips touch, if the pitch facet does not match or is pointed, sloped, or rounded, you often see the masseter or temporalysis muscle twitch. This occurs as the patient hesitates in their movement. That smooth transition back to the incisal edges of the centrals and laterals is important.

I also realized during my career that certain patients (teens, golfers, baseball players) would often stabilize their head while their teeth were cuspid tip to tip or in a crossover position at the point of their impact with the ball.

Improvements can be accomplished by simply taking the flat portion of a ½ J (wheel fine diamond) and creating matching facets on upper and lower cuspids. Polish them and both the leading and trailing bevels so that the movement becomes smooth. If the patient wants to stop cusp tip to cusp tip on the upper and lower cuspid, there is a stable stop and the muscles are comfortable.

To be continued…

The comprehensive exam sets the stage for the quality of your dentistry. The information you gather is instrumental in guiding your treatment plan, getting to know your patient, and helping you effectively relieve pain or discomfort.

The temporomandibular joint is one of the 4 exam areas that comprise a comprehensive functional exam. Ascertaining where we believe the disc is relative to the condyle and whether or not we detect the presence of inflammation are the goals. We want to understand if the joint is stable, adapted or currently undergoing breakdown.

Refresh Your Joint Exam Technique

A good place to start is with lateral pole location. While the patient is lying back, place three fingers lightly in the lateral pole region. Then have them open and close. As they are opening and closing, locate the lateral poles. Observe and record palpable joint noise sounds and motion. Make sure you are documenting your findings clearly throughout the process.

You should also reference maxillary midline to mandibular midline and record opening and closing deviations from the midline. There is so much that can be learned from this basic exam protocol.

Next, move on to joint auscultation in translation and excursions. Using your stethoscope to listen, you can direct the patient to again open and close without touching, as well as move their jaw excursively. You’ll verify palpable sounds and listen to both rotation and translation…

What do you consider critical elements of a joint and muscle exam? 

Do you feel reticent about having someone other than you use the facebow? 

A Spatial Reference Point Story

Recently over the holidays as I was “channel surfing” I came across the movie Apollo 13. This is one of those movies that no matter how many times I have watched it, I just have to stop and watch it one more time. Every time I do, I can’t help but get misty-eyed when it gets to the part when the crew make it back to Earth safely (SPOILER ALERT … But you probably read this in the history books anyway).

For me, there is one super exciting moment in the film when Astronaut James Lovell (aka Tom Hanks) has to find a reference point to correct their descent back to Earth from space or burn up on re-entry. Since he cannot use his on-board computers, he lines up his spaceship with the Earth in his window.

“Keep the Earth in the window!” A spatial reference point! Too much correction and their spaceship burns up on re-entry. Too little and they skip off the Earth’s atmosphere.

Make Your Facebow Process Simpler

In our dental offices, the facebow is used to give us a spatial reference point for mounting diagnostic or working models of our patient’s dentition. This is done onto an articulator that approximates the realities of our patient. Sure, you might be able to mount casts arbitrarily, but is your accuracy reproducible? The facebow is a simple tool in our armamentarium to make our life easier.

The question remains, “Is this a task that the dentist must perform?” In my office when we create exquisite dental mountings, I delegate this task to my awesome dental assistants.  With a little training they can do this immediately and the procedure only takes a few minutes.

This involvement is a great way for them to demonstrate their knowledge. It paves the way for more opportunities to open conversations about the Dentist’s Care, Skill, and Judgement. They become your chairside cheerleader and highlight your expertise. They will also express how a critical bite registration record or protrusive record performed by the dentist will only enhance the outcome of treatment.  

Information gathered through the use of a facebow makes our dentistry more predictable. It distinguishes you and your team as a highly trained dental practice.

Don’t burn up on re-entry or skip off into space. Glide effortlessly into beautiful predictable dentistry by using your facebow. Keep your Earth in the window!

This is part 2 in a series where Dr. Mike Crete describes an conservative esthetic case where he combined Invisalign and veneers.  Part one looks at helping the patient become aware of the possibilities. Read on for the conclusion.

A Smile Dialogue

… All of this conversation took place in about 5 minutes at the end of the patient’s initial hygiene examination. I then invited him to return for a ‘complimentary smile analysis’ appointment where I would take a series of digital photos and then sit down with him and talk about what we could do to improve his smile.   

I find I can build trust and credibility with a new patient by offering to see them for this complimentary appointment. It only takes about 20 minutes and I typically ‘convert’ the patient to a records appointment (comprehensive exam, X-rays, and mounted study models).

The records appointment was scheduled. More co-discovery revealed how significant Drew’s self-esteem was impacted by his smile and his ‘baby face and baby teeth.’ The records appointment was followed by a diagnostic wax up (or a “3D Design” as I like to call it when talking to patients).

Then a consultation was done to review treatment options. This was a formal case presentation using Powerpoint, photos, and mounted models. Drew’s mother sat in on the consultation appointment.

By having accurately mounted study models on a semi-adjustable articulator, I was able to determine I could give Drew an ideal occlusion AND a pleasing smile. This would involve some minor tooth movement using Invisalign for 6 months and then restoring his upper and lower anterior teeth with conservative porcelain veneers. His posterior teeth were equilibrated during the restorative process. Also, an upper bite guard was fabricated for nighttime wear and added protection of the restorations.  

Drew graduated from college approximately 18 months after I first met him. He completed an internship during his final semester and then was hired by the Fortune 500 company immediately following graduation. He recently got married and said to me, “After I had my teeth done everything in my life started to fall into place. I graduated, got a great job, and met the love of my life. Thanks, doc.”  

Changing a smile and changing a life. It’s being able to impact the lives of others in this way that makes it so rewarding to practice dentistry!  

There are three critical components to the incisal edge anatomy of anterior teeth. Understanding the function and esthetics of the pitch and two bevels is essential to creating an ideal patient result.

How can a clinician re-create the full anatomic form of the tooth in ceramics and composite? 

In my last blog on this topic, I discussed the dimensions, characterization, esthetics, restorative approach and challenge of mimicking ‘pitch‘ esthetics. Now, I’ll delve into mastering the bevels to create superior restorative results. Combining an esthetic pitch with functional bevels will ensure a smooth composite or ceramic outcome.

Components of Incisal Edge Anatomy Function and Esthetics: Bevels

The two bevels can be found on alternately the labial and the lingual of the transition zone between the pitch and these surfaces. They are often called the leading edge and the trailing edge.

Bevels

Dimensions: The bevels on both sides have a variable width. They can be between less than a millimeter to multiple millimeters long.

Characterization: The bevels lengthen in patients who grind their teeth in an excursive pathway pattern. Patients who parafunction edge to edge might eliminate the bevel. This makes it easier to shear enamel off on the labial or lingual side of the tooth. It also could result in chipping the edge enamel.

Function: The bevel is a transition zone to create smooth functional movement passing from excursive movements onto the pitch. Intercuspal stops on lower incisors are often on or gingival to the bevel.

Whether you are finalizing an equilibration, the occlusion on composites, or ceramics, perfecting anterior guidance is all about both pitch and bevel surfaces. These critical components are a great example of marrying form and function in your technique.

What is your restorative approach for recreating incisal edge anatomy? We’d love to hear from you in the comments! 

The incisal edge anatomy of anterior teeth is quite complex. This complexity is fundamental to the esthetics of the tooth, as well as the function of incisors. How do we re-create the full anatomic form of the tooth in ceramics and composite? 

Components of Incisal Edge Anatomy Function and Esthetics: Pitch

When the full anatomic form is not precisely recreated, this can lead to esthetic and functional challenges. To successfully mimic this form, the clinician can rely on three components of incisal edges (from a lateral perspective): 1 pitch and 2 bevels.

We can visualize the pitch as the flat top of the incisal edge.

Pitch

Dimensions: Labio-lingual width of at least 1mm that increases from attrition or parafunction in edge to edge position.

Characterization: Pitch is not always parallel to the horizon and its relative position is dependent on the inclination of the incisor. Incisors are inclined just a little bit further to the labial at the incisal edge and the pitch has an upward slant toward the lingual.

Esthetics: The tooth shape and inclination results in an incisal edge esthetic of thinner enamel at the labio-incisal junction. It also creates the highly desirable visual translucence. Leveling the pitch to the horizon can change light reflection which is critical to esthetics of the tooth.

Restorative Approach: Often in ceramics we create a pitch that is level to the horizon and has decreased width of the pitch. This can compromise the esthetics of the translucency, but that can be gained back using stains.

Challenge: The challenge with this shape change in ceramics is that patients often sit in edge to edge position during parafunction. Insufficient pitch width may result in the patient experiencing functional challenges, not finding a comfortable spot to rest and increased parafunctional movement.

I’ll expand on understanding the two bevels in my next incisal edge anatomy blog …

What aspects of incisal edge anatomy do you find most challenging? Let us know in the comments!