Since it is called "Occlusal Vertical Dimension" so it depends on the occluding of the occlusal surfaces of the teeth. When the patient being edentulous and miss all his teeth so there is no "occlusal" table to "stop" the vertical dimension at a specific point/distance. Therefore we can't call any relation between the upper and lower jaws in ednetulous patient as "Occlusal Vertical Dimension" otherwise it can be called "Rest/Resting Vertical Dimension". The (RVD) can be used to measure (OVD).

In my own opinion, such mastication and function with the ridges cannot be explained or interpreted as "Occlusal Stops" i edentulous patients. the proprioceptors and neuromascular control might play the important role in such work, as well as the size of the food particle/bolus.

Reviewing the literature regarding the methods and instruments used for measuring this distance in edentulous patients. to summarize that, it can be divided into two main categories:

1- Pre-extraction Records:

which deal with the measurement of the (OVD) BEFORE the patient being edentulous and preserving this record to be used after edentulousness stage. (Casts, OPG, facial measurements, photograph of the face, .....) are examples for such method.

2- Post-extraction Records:

this method based on the measurement after the patient lose all his/her teeth. measuring the distance between upper and lower jaws using (RVD) then the (OVD) can be extract by decrease freeway space (2-4 mm) from the (RVD). many methods have been exhibited in the literature for this purpose (The most common methods are; Willis gauge which measures the distance from the septum of the nose to the under of the chin and  the other method is Pleasure's method which measures the distance between two dots; one on the top of the nose and the other is on the top of the chin).

Recently, many methods have been proposed to measure the distance between two point/dots away from the movable mandible.

Ladda,2013 suggests the measurement of the Index finger (for males) and the Little finger (for females) to be used as alternative distance for OVD in edentulous patients.

Basent, 2015 suggests the use of the thumb finger to be used.

One study has been carried out in Serbia 2015 suggested using of Vowel letters (O & E) to be used by specific simple equation to measure the (OVD) in edentulous patients.

Thank you dear Dr. Faheemuddin Muhammad.

Thankyou Dr.Mohammed Nasser Alhajj! you have unwound my entangled thoughts. another question is probing my mind; what would the vertical position of the jaws be called in an edentulous patient when his/her mouth is closed? can it just be called "vertical dimension with mouth closed" ?

Dear Dr. Faheemuddin.

The edentulous jaws cannot completely close to each other (the upper ridge cannot completely close to the lower ridge), so we cannot find "Occlusal" vertical dimension otherwise we can use Resting vertical dimension to describe the relation between the upper and lower jaws.

Dr. Faheemuddin.

Let me ask you one question,

If we seek for the methods to Re-establishment of the LOST vertical dimension of the edntulous patients after they lost all their natural teeth, What are the benefits of measuring the distance between the "occluded" upper and lower  "edentulous" jaws?

Thank you

actually, i was thinking on the same lines...i was assuming..if we measure the vertical dimension with the jaws closed and take the RVD we can have an idea of the space available between the ridges , because at times, the inter ridge space is unfavorable for our prosthesis such as implant supported/ tooth supported overdentures etc.

I agree with dr Mohammed Nasser Alhajj that "Occlusal Vertical Dimension" depends on the occlusal surfaces of teeth, and since edentulous patients have no teeth, so there is no definite occlusal stop, and in that case, vertical dimension of occlusion can only be assumed by variable methods, most commonly, subtracting (2-4 mm) freeway space from RVD.

However, I think dr Faheemuddin Muhammad is assuming that if the vertical dimension of edentulous patients can be measured with the jaws closed, then the difference between estimated VDO and the vertical dimension with jaws closed can give an idea about the available inter-ridge space to detect suitability of the planned prosthesis.

For me in my research work, I used tentative jaw relation to detect suitability of available inter-arch space with the planned prosthesis, however your idea dr Faheemuddin Muhammad can be a good research point that may discover a new technique that would save clinicians effort and time.

Good Luck in that !

Best wishes.

Dear Dr Muhammad

When old method serves us and our patients what is the reason for searching an alternative?

I have used the old measuring method (distance between 2 dots; one on the nose and one on the chin (over the height of contour). Till now I have not encountered any problem with this method in the last 15 years.

Kindest regards

First of all, to use the concept “Occlusal Vertical Dimension” on edentate patients is a contradiction in terms as such patients have no occlusal surfaces. The mandibular physiologic rest position is a more useful concept. This constitutes the basis for one of the methods of determining a suitable vertical intermaxillary relationship for denture wearers. However there is a plethora of methods to this end. They range from mechanical methods such as various pre-extraction records, measurements of previous dentures, parallelism of the ridges etc. to equally various physiological methods, including physiologic rest position, phonetics, swallowing threshold and patient-reported perception of comfort.

In older dental literature it was erroneously assumed that the physiologic rest position of the mandible was unalterable (Niswonger in the 1930-ies), and that any deviation from the “correct” physiologic rest position might result in patient rejection of the denture. However, numerous publications in the second half of the 19th century have abundantly demonstrated two facts: Firstly, any method attempting to record a suitable intermaxillary distance in the edentate shows great variability. In simpler terms, these methods have one thing in common: they are all unreliable.  Secondly, most denture wearers have great tolerance in this respect.

The latter fact does not preclude that there are limits to patient tolerance if the deviation is too great. Because of the unreliability of methods of recording a suitable intermaxillary distance in the edentate, once in a rare while one has to accept a remake of dentures at one’s own cost, and this fact has to be incorporated in one’s general fee for the treatment.

As can be inferred, clinical experience and personal skill rather than scientific methods determine the degree of success in this matter. My advice to the clinician is to use several of the above methods for a preliminary recording – controlling one against the other. In this evaluation, the personal preference of the undersigned consists of simply regarding the facial contour with the occlusal rims in place and evaluate if the face looks elongated, puckered or “normal”. This evaluation should then be repeated at the try-in stage. At both stages it is important to bring in the patient and listen to his or her opinion. it is important.

Dr. Faheemuddin, I agree with the others suggestions. If your aim is to see if the space is enough for prostheses - the ideal way is to tentative jaw relation and articulation of the models. I think your thought of measuring rest VD Vs closed VD is more clinical and will result in unreliable measurements for treatment planning.

Dear Colleagues clinicans, what with temporo-mandibular joints (TMJs)? Is it setting of the occlusion not intended to correct setting madibular condylar relationship with respect to the acetabulum. Hence, there is OVD anf RVD. theoretically.... But what it means correct RVD and corect condylar position after many years of edentolouism and mastication without teeth ? The TMJs can remodel during edentate state (according to my intuition) 

Are there any precision data about TMJ difference in edentate population wearing denture in comparing with not-wearing ? In practice, there are a few cilinical methods of seting OVD and TMJs are not sensitive on underestimation, while overestimation only on very high level can lead to an misalignments.

 I AGREE WITH DR Mohammed Nasser Alhajj 

 no we can't measure the lost OVD by utilizing the Rest vertical dimension and Vertical dimension when the mouth is closed for edentulous patients as when the patient were without teeth and closed on their edentulous ridge the V D is beyond the OVD due to the lose of the teeth and their supporting tissue thus the patients need to restore all the missing tissue to obtain accurate VD 

VDO is a space between maxilla and muscle positioned mandible. Repeated contractual length of elevators determine VDO. Studies have shown that Length of muscle at rest keeps changing from one person to another and within the same patient under different conditions but contractual length remain constant. So dimensions of VDO is basically the distance between Zygomatic arch to angle of the mandible. 

Even when patient become edentulous, VDO remains constant i.e. the contracted length of elevator, when mandible is in CR  . Just because there are no occlusal stops and alveolar processes have resorbed patient moves his mandible forward for chewing making condyle to move downward and forward.

So measured length from zygomatic arch to angle of the mandible when condyles are in CR should act as a reliable guide for determining VDO in edentulous cases.