The study of prosthodontics allows us to create appliances for those who are missing teeth, and give those who are edentulous a chance to speak and chew properly again. Edentulism (the process of losing teeth) comes with it a host of issues – the syndrome we are going to discuss today has a ‘combination’ of those issues, for which it received its name.

What Are A Few Problems Associated With Losing Teeth?

Losing teeth is not just an esthetic issue – it’s a nutrition issue, a mental wellness issue, and a quality of life issue. Losing teeth results in a loss of function, and those who are edentulous can’t eat like they could before. This includes focusing on soft diets that are not rich in nutrition – no more steaks full of protein. Along with loss of function, some may suffer from mental health issues that revolve around not having an esthetic set of teeth. The way your face looks and the way your mouth functions all change as you lose teeth. Combination syndrome involves a bit of all of these.

How Does Combination Syndrome Occur?

Combination syndrome is specific to a certain class of edentulism. Those who only have their natural anterior teeth, and no remaining upper teeth, have been observed to suffer from this syndrome¹. As we lose teeth, the bone that once held the teeth begins to resorb. This is due to a fact that many do not realize about the bones in their body – they are not the solid, hard, lifeless substance that we associate with those who have passed. Bones are actually constantly growing and resorbing, new bone being laid every day. However, once a tooth is lost, the forces that were once placed on that bone (and signaling it to remodel), are also lost. The bone that once held teeth eventually becomes resorbed by the body, and issues such as combination syndrome arise.

The issue of combination syndrome primarily lies in an occlusion (or bite) that is traumatic, along with the resorption of bone. As those with a removable partial resorb bone in the posterior alveolar ridge, a posterior open bite develops. This lack of posterior contacts develops an anterior shift of masticatory function (patients begin focusing their bite on their front teeth). With this shift includes more forces placed on the upper anterior bone, as well. This large amount of force results in a loss of more bone in the upper anterior. Let’s review so far – the posterior bone in the lower jaw is resorbing due to a lack of teeth (as well as the mandible’s fast resorption rate when compared to the maxilla), and the anterior bone in the maxilla is resorbing due to the strong masticatory forces².

With the posterior bite open, the maxillary tuberosities (a bundle of bone on the back of your maxilla) begin a downward growth. The lower anterior teeth appear to be extruded – splayed out forward – as they traumatically occlude with the upper anterior. Now that we know how combination syndrome comes to fruition, let’s review the characteristics that we’ve started to discuss.

What Are The Characteristic Features of Combination Syndrome?

Combination syndrome, like stated above, occurs in those who have completely lost their upper teeth but still have remaining natural lower front teeth. Those who are interested in a removable lower partial denture and full upper denture may be concerned with combination syndrome. The features are widely known:

• Loss of bone from the anterior maxilla
• Loss of bone from the posterior mandible
• Overgrowth of the maxillary tuberosities
• Extrusion of the lower anterior teeth

Out of these characteristics, the two most commonly seen are the resorption of the anterior maxilla and a posterior open bite. Not all symptoms are always observed in this syndrome.

Should We Be Worried About Combination Syndrome?

As of now, combination syndrome is still a debated topic and its prevalence is still surrounded in controversy. It is regarded as a rare syndrome, only occurring in 24% of those with a full upper denture and a removable partial lower denture². In fact, one study in 2019 concluded from their sample size of 99 patients that the syndrome was non-existent in their cohort, stating –

‘Evidence supporting the existence of Combination Syndrome was not discovered in this research. Prevalence of Combination Syndrome appeared to be low or non-existent. Patient treatment modalities and teaching in relation to Combination Syndrome may need to be modified³’

This isn’t to say the study wasn’t completely conclusive – at least 8 of the patients were seen to have at least two of the symptoms. Where things get complicated is the complete lack of evidence and literature regarding this syndrome. A literature review was performed in 2003 for this reason. The review found that, at the time, there were no randomized controlled trials for combination syndrome. The study quotes –

‘No epidemiologic study of the various features related to combination syndrome has been published. There is no evidence that a mandibular removable partial denture can prevent the development of the events described⁵’

Furthermore, the study concludes that the syndrome does not meet the criteria to be designated a medical syndrome. With this in mind, a practitioner should be able to identify the features of the syndrome but patients who are concerned with it developing may be unnecessarily doing so.

To Summarize:

• Combination syndrome affects those who have no upper teeth, but remaining anterior lower teeth
• Combination syndrome is the result of bone resorption in the posterior mandible and traumatic occlusion
• The syndrome can leave patients with ill-fitting dentures and overgrown maxillary tuberosities
• The syndrome has not had sufficient evidence to classify it correctly
• Patients who are worried about the syndrome should understand that a correctly made denture should reduce the chances of the syndrome occuring

References:

¹The Glossary of Prosthodontic Terms: Ninth Edition. J Prosthet Dent. 2017 May;117(5S):e1-e105. doi: 10.1016/j.prosdent.2016.12.001. PMID: 28418832.

²Tolstunov, L. (2011, April 01). Combination syndrome symptomatology and treatment: Compendium. Retrieved March 18, 2021, from https://www.aegisdentalnetwork.com/cced/2011/04/combination-syndrome-symptomatology-and-treatment

³Bagga, R., Robb, N. D., & Fenlon, M. R. (2019). An investigation into the prevalence of Combination Syndrome. Journal of Dentistry. https://doi.org/10.1016/j.jdent.2019.01.016

⁴Madan N, Datta K. Combination syndrome. J Indian Prosthodont Soc 2006;6:10-3

⁵Palmqvist, S., Carlsson, G. E., & Owall, B. (2003). The combination syndrome: a literature review. The Journal of prosthetic dentistry, 90(3), 270–275. https://doi.org/10.1016/s0022-3913(03)00471-2

⁶Jameson, W. (2021). Needed: A paradigm shift in the approach to Treating Combination Cases William S. JAMESON, BS, DDS, FACP, FICD. Retrieved March 22, 2021, from https://www.dentaltown.com/magazine/article/2736/needed-a-paradigm-shift-in-the-approach-to-treating-combination-cases

Liability Statement:

The medical advice given in this blog should only be utilized by a medical professional who has received a medical degree. I am not responsible for the medical advice given in this blog and each case should be reviewed extensively with sources outside my blog. This blog is for education purposes only and is not meant as a substitute for an academic institution.