# Increase of bigonial distance after BSSO



## Pendejo (Jan 17, 2020)

Posterior mandibular widening secondary to advancement sagittal split osteotomy: A retrospective study


Patients sometimes spontaneously report a modification of the width of their lower face after an advancement bilateral sagittal split osteotomy (ABSSO…




www.sciencedirect.com





The first goal of the study was to assess the impact of ABSSO (advancement bilateral sagittal split osteotomy) on the BGD (bigonial distance), one day and one year after surgery. The second objective was to look for a possible relation between the increase of BGD and the amount of mandibular advancement.



> All consecutive patients operated between August 2011 and October 2013 in our department for a class II malocclusion by mean of an isolated ABSSO were retrospectively included in the study. Concomitant wisdom tooth extraction was allowed. Patients operated with a combination of orthognathic procedures (ABSSO and mandibular contraction, and/or genioplasty, and/or Le Fort I maxillary osteotomy) and patients with incomplete records were excluded.



The technique used in the study was the Obwegeser-Dal Pont II technique.


*Measurement methods*
The amount of mandibular advancement was measured by comparison between pre- and postoperative lateral teleradiographies made in centric occlusal positionand taken one day and one year postoperatively. In order to be reproducible, measures were made between the anterior face of incisors or orthodontic brackets and projected on a horizontal axis (fig. 2).








> Figure 2. Example of measures on lateral teleradiographies in centric occlusal position. A. Before surgery. B. Postoperative day 1 (radiological advancementhere is 7.362.45 = 4.91 mm).



The amount of posterior mandibular widening was assessed by measuring the variations of the BGD on frontal teleradio-graphies using the same chronology. Gonions were spotted as the most lateral points located on each mandibular angle (fig. 3).






> Figure 3. Example of measures on frontal teleradiographies. A. Before surgery. B. Postoperative day 1. C. Postoperative year 1 (ICD = intercanthal distance;BGD = bigonial distance).



Intrinsic reliability was evaluated by measuring the medial intercanthal distance (ICD), considered as constant, on pre-operative and one day postoperative frontal teleradiographies (fig. 3).

*Results*
One day after surgery, BGD increased in all patients. Statistical analysis reported a significant mean increase of 9.8 mm(P<103). One year after surgery, mean BGD increase was 4 mm and remained significant compared with preoperative value(P<103). BGD decreased at one year postoperative in 9 patients (18%) comparatively to the preoperative measure. Schematic representation of all the BGD measures made by both evaluators shoved an ‘‘increase-decrease’’ profile (fig. 5).







> Figure 5. Evolution of bigonial distance (BGD) measures for all the patients (black lines: measures made by investigator A; grey lines: measures made by investigator B).



Not significant relation was found between the amount of mandibular advancement and the postoperative variation of the BGD as shown by the absence of any specific pattern in the relation between these two variables (fig. 6).







> Figure 6. Bigonial distance (BGD) evolution at one year postoperative according to mandibular advancement measured on lateral teleradiographies.










> Figure 9. Clinical aspect of positive effect of lower face widening on a male patient. A. Before surgery. B. One year after surgery.




*Discussion*
BGD increase after ABSSO can first be explained by the anatomy. Because of the V-shape of the mandible, there will be an interference inside the osteotomy line during advancement of the dental arch, responsible for lateral displacement of the lateral valve on each side (fig. 7).







> Figure 7. Schematic illustration of lateral movements of the lateral valves induced by dental arch advancement; superior view of the V-shaped mandible. Left: before advancement; right: after advancement.




The osteotomy technique may be of great importance in this phenomenon. In the technique described by Epker, residual lingual cortical bone on the lateral valve may interfere with the medial valve, responsible for a lateral flaring of the mandibular angles. The use of the Obwegeser-Dalpont II technique, may reduce these bony interferences, as the osteotomy is extended down to the basilar edge. The kind of fixation must also be considered. Semi-rigid fixation, might facilitate lateral flaring of mandibular angles. It would therefore be relevant to compare semi-rigid and rigid fixation. However, temporo-mandibular joint disorders seem to be more frequent when using rigid fixation techniques because of more severe modifications in condylar position induced by these devices.

Posterior mandibular widening seems to reduce one year aftersurgery, even if it remains significant. 9 patients(18%) showed a decrease in their posterior mandibular width at the one-year control. This was significantly observed in the youngest patients.

The hypothesis proposed in the study is that mandibular bone remodeling induced modifications in muscular strains is more important in young patients than in older ones.

Modifications induced by mandibular advancement on mus-cular strains and their effect on bone remodeling process mayexplain the decrease of posterior mandibular width one yearafter surgery in young patients.


_*TL;DR:*_

Bigonial distance mean increase was 4mm after BSSO using the Obwegeser-Dal Pont II technique
The bigonial distance decreased in some patients, especially on the younger ones.
There was no relation between the amount of mandibular advancement and the increase of BGD.


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## Pendejo (Jan 17, 2020)

I wanted to include a pic showing the diference between the Obwegeser-Dalpont and Epker method but i only could find this:






@Dr Shekelberg (or anybody else) do you think you could find a picture that shows the differences better?


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## Deleted member 3990 (Jan 17, 2020)

Pendejo said:


> I wanted to include a pic showing the diference between the Obwegeser-Dalpont and Epker method but i only could find this:
> 
> View attachment 232587
> 
> ...


the cut at the ramus is different


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## MogTheMogger (Jan 17, 2020)

absolute peak high iq, this is so motivating and ascending as fuuuuuuuuuck bro


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## Pendejo (Jan 17, 2020)

Dr Shekelberg said:


> the cut at the ramus is different


Yeah i know.

I just wanted a pic showing both methods from a superior view, like the one on the thread but with the Epker method too.


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## reptiles (Jan 17, 2020)

Pendejo said:


> Posterior mandibular widening secondary to advancement sagittal split osteotomy: A retrospective study
> 
> 
> Patients sometimes spontaneously report a modification of the width of their lower face after an advancement bilateral sagittal split osteotomy (ABSSO…
> ...






Very good fucking thread


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## forwardgrowth (Jan 17, 2020)

reptiles said:


> Very good fucking thread


THIS IS FACT
what is better to fix jaw width IMDO or BSSO?
Can this method flare the gonion like this


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## Sergio-OMS (Jan 19, 2020)

With IMDO the distance between the gonia gradually become shorter, although the mandible become wider just at the level of the first molars. That effect, along with the masseter muscles, widen the mandible more than with BSSO.

Hope this helps,

Sergio


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## Pendejo (Jan 19, 2020)

Sergio-OMS said:


> With IMDO the distance between the gonia gradually become shorter, although the mandible become wider just at the level of the first molars.


So the bigonial distance becomes shorter compared to the rest of the mandible or IMDO actually decreases the bigonial distance?


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## Sergio-OMS (Jan 19, 2020)

We haven't processed the whole data but the geometrical analysis on the computer of a single case would show a slight decrease of the distance between the gonia, as you can see here: 

But, as I said, the whole effect would be as if the mandible became much wider than in BSSO. It is not all about some particular dots placed in the bones. As a matter of fact, as the mandibular intermolar distance increases, a larger amount of maxillary expansion is needed. That is normally a desired effect, isn't it?


Hope this helps,

Sergio


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## Pendejo (Jan 19, 2020)

Sergio-OMS said:


> We haven't processed the whole data but the geometrical analysis on the computer of a single case would show a slight decrease of the distance between the gonia, as you can see here:
> 
> But, as I said, the whole effect would be as if the mandible became much wider than in BSSO. It is not all about some particular dots placed in the bones. As a matter of fact, as the mandibular intermolar distance increases, a larger amount of maxillary expansion is needed. That is normally a desired effect, isn't it?
> 
> ...



Thanks for the answer.

@chadpreetinthemaking look at this.


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## Darkstrand (Jan 19, 2020)

Sergio-OMS said:


> We haven't processed the whole data but the geometrical analysis on the computer of a single case would show a slight decrease of the distance between the gonia, as you can see here:
> 
> But, as I said, the whole effect would be as if the mandible became much wider than in BSSO. It is not all about some particular dots placed in the bones. As a matter of fact, as the mandibular intermolar distance increases, a larger amount of maxillary expansion is needed. That is normally a desired effect, isn't it?
> 
> ...



Are you actually a maxillofacial surgeon?


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## Sergio-OMS (Jan 19, 2020)

I am, indeed: https://www.linkedin.com/in/maxilofacial


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## Ceamce (Jan 19, 2020)

Sergio-OMS said:


> I am, indeed: https://www.linkedin.com/in/maxilofacial


Veo que eres de españa, yo soy de Argentina y fui a una clinica oral y me dijeron que soy buen candidato a cirugía ortognatica. Puedes pasarte por mi post y ver mi foto de perfil y dejar una opinión? Habia gente que me recomendaba lefort 2 pero me parece algo exagerado.


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## Sergio-OMS (Jan 19, 2020)

Ceamce said:


> Veo que eres de españa, yo soy de Argentina y fui a una clinica oral y me dijeron que soy buen candidato a cirugía ortognatica. Puedes pasarte por mi post y ver mi foto de perfil y dejar una opinión? Habia gente que me recomendaba lefort 2 pero me parece algo exagerado.



No, lo siento, no puedo dar mi opinión con tan poca información. Sí que puedo decirte que hacer un Le Fort 2 me parece una locura.


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## GetThatBread (Jan 19, 2020)

BSSO is the true ascension


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## Darkstrand (Jan 19, 2020)

Sergio-OMS said:


> I am, indeed: https://www.linkedin.com/in/maxilofacial


What do you think of the idea of puncturing the nasal sutures up the remains of the frontal suture to achieve more harmonic expansion during MSE


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## Sergio-OMS (Jan 19, 2020)

Darkstrand said:


> What do you think of the idea of puncturing the nasal sutures up the remains of the frontal suture to achieve more harmonic expansion during MSE


Does anybody do that? 😳


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## Darkstrand (Jan 19, 2020)

Sergio-OMS said:


> Does anybody do that? 😳


I came up with this idea and I want to find someone that does that, I already heard from an orthodontist it theoretically should work, but I need someone to actually do this on me


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## Sergio-OMS (Jan 19, 2020)

Darkstrand said:


> I came up with this idea and I want to find someone that does that, I already heard from an orthodontist it theoretically should work, but I need someone to actually do this on me



Well, we are almost 8 billion people, I am confident that you will.


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## chadpreetinthemaking (Jan 19, 2020)

Pendejo said:


> Thanks for the answer.
> 
> @chadpreetinthemaking look at this.


Bro cheers, im seriously consudering IMDO. This is a good thing right?


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## Pendejo (Jan 19, 2020)

chadpreetinthemaking said:


> Bro cheers, im seriously consudering IMDO. This is a good thing right?


Did you see the video Sergio posted?
It would move the mandible forward and make it wider but the bigonial distance would decrease slightly.

I wonder if the decrease of the bigonial distance could be avoided by getting a BSSO + SARPE instead. @Sergio-OMS


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## chadpreetinthemaking (Jan 19, 2020)

Pendejo said:


> Did you see the video Sergio posted?
> It would move the mandible forward and make it wider but the bigonial distance would decrease slightly.
> 
> I wonder if the decrease of the bigonial distance could be avoided by getting a BSSO + SARPE instead. @Sergio-OMS


I need SARPE the most tbh, narrow mouth/palate is such a failo, makes no sense that I would have it with a forward grown maxilla.


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## Sergio-OMS (Jan 19, 2020)

Pendejo said:


> Did you see the video Sergio posted?
> It would move the mandible forward and make it wider but the bigonial distance would decrease slightly.
> 
> I wonder if the decrease of the bigonial distance could be avoided by getting a BSSO + SARPE instead. @Sergio-OMS



That inwards rotation of the mandibular gonia is negligible and the final effect on the size of the mandible is much larger and nicer with IMDO than with BSSO. And this is not counting on the effect of the upper maxillary expansion needed for IMDO.
Well, both BSSO and IMDO need a maxillary expansion (by means of SARPE, MSE or 2/3 piece Le Fort 1) but the expansion needed with IMDO is larger. This is good.


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## Pendejo (Jan 20, 2020)

Sergio-OMS said:


> That inwards rotation of the mandibular gonia is negligible and the final effect on the size of the mandible is much larger and nicer with IMDO than with BSSO. And this is not counting on the effect of the upper maxillary expansion needed for IMDO.
> Well, both BSSO and IMDO need a maxillary expansion (by means of SARPE, MSE or 2/3 piece Le Fort 1) but the expansion needed with IMDO is larger. This is good.


I understand.

Anyway what i wanted to ask on my comment was if MSDO combined with BSSO could replicate the results of IMDO without rotating the gonials inwards, i just confused MSDO with SARPE, my bad.

Do you think it would work?


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## Sergio-OMS (Jan 20, 2020)

Pendejo said:


> I understand.
> 
> Anyway what i wanted to ask on my comment was if MSDO combined with BSSO could replicate the results of IMDO without rotating the gonials inwards, i just confused MSDO with SARPE, my bad.
> 
> Do you think it would work?



I don't know, I have never combined BSSO + MSDO.

Using my basic knowledge on trigonometry I would say that MSDO widens the anterior mandible (including the chin and IMDO widens the posterior (maybe no the gonia, it widens at the level of the molars).

To be honest, I think this is just plain speculation. And IMDO post-op isn't easy in adults.


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## Reoreyh (Jan 20, 2020)

Can I be confident of these gonial angle gains if I'm getting a BSSO or do I need to request this from my surgeon? How do I ask what technique he's using?


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## superhans (Jan 21, 2020)

GetThatBread said:


> BSSO is the true ascension


it is most natural ascension, because you use your own bones, and not implants.


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## GetThatBread (Jan 21, 2020)

superhans said:


> it is most natural ascension, because you use your own bones, and not implants.


MSDO + MSE also, that’s basically a crazy fWHR increase + ascension


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## Ceamce (Jan 21, 2020)

GetThatBread said:


> MSDO + MSE also, that’s basically a crazy fWHR increase + ascension


Msdo is a simple surgery?


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## Sergio-OMS (Jan 22, 2020)

Ceamce said:


> Msdo is a simple surgery?



It is not technically difficult. But, is it necessary? They are associated risks, something to think about.


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## Ceamce (Jan 22, 2020)

Sergio-OMS said:


> It is not technically difficult. But, is it necessary? They are associated risks, something to think about.


because I am studying with an orthodontist to put on MSE. (mainly to improve breathing and widen the palate) and the upper part (which expands) should be aligned with the jaw


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## Sergio-OMS (Jan 22, 2020)

Ceamce said:


> because I am studying with an orthodontist to put on MSE. (mainly to improve breathing and widen the palate) and the upper part (which expands) should be aligned with the jaw


Your orthodontist will let you know if it is necessary. Normally a nice upper expansion is possible without the need of a MSDO procedure, only adjusting the inclination and position of the lower teeth.


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## anti caking agents (Jan 22, 2020)

Can you do a BSSO if your occlusion is perfect in terms of molars a nd you only have a class II malocclusion due to overjet of the anterior upper incisors or would you need to combine it with a Lefort 1 in that case?


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## kota (Jan 22, 2020)

anti caking agents said:


> Can you do a BSSO if your occlusion is perfect in terms of molars a nd you only have a class II malocclusion due to overjet of the anterior upper incisors or would you need to combine it with a Lefort 1 in that case?


You need to combine them to keep the occlusion.


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## Sergio-OMS (Jan 22, 2020)

anti caking agents said:


> Can you do a BSSO if your occlusion is perfect in terms of molars a nd you only have a class II malocclusion due to overjet of the anterior upper incisors or would you need to combine it with a Lefort 1 in that case?


Sometimes doing just a BSSO is possible. + orthodontics, of course .


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## Blackpill3d (Jan 23, 2020)

big if true


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## forwardgrowth (Jan 25, 2020)

Sergio-OMS said:


> I don't know, I have never combined BSSO + MSDO.
> 
> Using my basic knowledge on trigonometry I would say that MSDO widens the anterior mandible (including the chin and IMDO widens the posterior (maybe no the gonia, it widens at the level of the molars).
> 
> To be honest, I think this is just plain speculation. And IMDO post-op isn't easy in adults.


So the level of widening is not occurring at gonions but at the midpoint of the mandible at the second premolars..?


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## Golden Glass (Jan 26, 2020)

Sergio-OMS said:


> No, lo siento, no puedo dar mi opinión con tan poca información. Sí que puedo decirte que hacer un Le Fort 2 me parece una locura.


Este foro está lleno de muchachos quien se quieren hacer las cirugías que ayuden a tener un viscerocraneo lo más atractivo posible.

Hay gente interesados en Lefort III y Orbital Box Ostoeotomy


¿Te molestaría si te mando mi radiografía por mensaje privado?


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## Sergio-OMS (Jan 26, 2020)

forwardgrowth said:


> So the level of widening is not occurring at gonions but at the midpoint of the mandible at the second premolars..?



At the level of the osteotomy, precisely.


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## Pendejo (Jan 26, 2020)

Reoreyh said:


> Can I be confident of these gonial angle gains if I'm getting a BSSO or do I need to request this from my surgeon? How do I ask what technique he's using?


Ask him directly, the technique used in the study was the Obwegeser-Dal Pont II technique.


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## PubertyMaxxer (Jan 26, 2020)

Sergio-OMS said:


> Your orthodontist will let you know if it is necessary. Normally a nice upper expansion is possible without the need of a MSDO procedure, only adjusting the inclination and position of the lower teeth.


How much mm can i expand with mse usually assuming i have perfect occlusion now without needing msdo, just using braces for teeth inclination?


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## Sergio-OMS (Jan 26, 2020)

PubertyMaxxer said:


> How much mm can i expand with mse usually assuming i have perfect occlusion now without needing msdo, just using braces for teeth inclination?



If you have a perfect occlusion the expansion will be limited by the torque of the lower molars, the bone around their roots and the willingness of your orthodontist to do that treatment.

maybe 10 mm tops? that’s being really optimistic about all those factors.


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## PubertyMaxxer (Jan 26, 2020)

Sergio-OMS said:


> If you have a perfect occlusion the expansion will be limited by the torque of the lower molars, the bone around their roots and the willingness of your orthodontist to do that treatment.
> 
> maybe 10 mm tops? that’s being really optimistic about all those factors.


Woah thats a lot. lifefuel


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## Sergio-OMS (Jan 26, 2020)

PubertyMaxxer said:


> Woah thats a lot. lifefuel



Well don’t expect that result. And you need to start from a narrow palate and not so perfect occlusion (apparently perfect but not to the trained eye)


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## PubertyMaxxer (Jan 26, 2020)

Sergio-OMS said:


> Well don’t expect that result. And you need to start from a narrow palate and not so perfect occlusion (apparently perfect but not to the trained eye)


If i could expand 8mm with mse and just get braces for inclination it would still hive me a mouthwidth and good cheekbone gains right?


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## Sergio-OMS (Jan 26, 2020)

Effects on the cheekbones are more limited as there are more sutures to split and they are distant from the palate. Their distance would increase by 2-3 mm maybe ?


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## Golden Glass (Jan 26, 2020)

Sergio-OMS said:


> Effects on the cheekbones are more limited as there are more sutures to split and they are distant from the palate. Their distance would increase by 2-3 mm maybe ?


People get implants there just to get a 3-4 mm increase so that would be good.


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## forwardgrowth (Jan 26, 2020)

Sergio-OMS said:


> Effects on the cheekbones are more limited as there are more sutures to split and they are distant from the palate. Their distance would increase by 2-3 mm maybe ?


Can you perform MSE for aesthetics ?


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## GetThatBread (Feb 5, 2020)

So MSDO can’t increase bigonial width and masculinize the lower jaw?

https://looksmax.org/threads/how-to-increase-bigonial-angle-mandible-width.87258/post-1507583
What about this vid? Does the lower jaw not increase laterally?


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## Sergio-OMS (Feb 6, 2020)

GetThatBread said:


> So MSDO can’t increase bigonial width and masculinize the lower jaw?
> 
> https://looksmax.org/threads/how-to-increase-bigonial-angle-mandible-width.87258/post-1507583
> What about this vid? Does the lower jaw not increase laterally?



In that animation (not actual simulation) the mandibular condyles are displaced laterally and “pushed out” of the glenoid fossae. I don’t think actually happens, it would actually cause TMJ problems but it’s also difficult from a biomechanical point of view (I can’t prove it to you though, but it look like you should first prove what you say).

To me, condyles act as a pivot point. So, can you imagine the actual widening at the back part of the mandible if the condyles are the pivot point?


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## GetThatBread (Feb 6, 2020)

Sergio-OMS said:


> In that animation (not actual simulation) the mandibular condyles are displaced laterally and “pushed out” of the glenoid fossae. I don’t think actually happens, it would actually cause TMJ problems but it’s also difficult from a biomechanical point of view (I can’t prove it to you though, but it look like you should first prove what you say).
> 
> To me, condyles act as a pivot point. So, can you imagine the actual widening at the back part of the mandible if the condyles are the pivot point?


I see then what does MSDO do? Just widens the chin? Is The actual widening of the mandible possible? Wouldn’t it cause TMJ if the maxilla isn’t matching the condyles? My ortho told me to get MSE and MSDO at the same time so TMJ issues doesn’t occur. The arrows pointing are MSE and MSDO in conjunction expanding the face laterally.


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## Sergio-OMS (Feb 6, 2020)

MSDO can be useful to the orthodontist (and the patient, of course) to get a proper bite, specially at the front part (canines). Not really more than that. Actual posterior widening is, in my opinion, negligible.


forwardgrowth said:


> Can you perform MSE for aesthetics ?



sorry I didn’t see this one.

can you explain a bit more? Most orthodontic treatments are done with an aesthetic motivation or achieve a better aesthetic result.


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## Gonion (Feb 7, 2020)

Sergio-OMS said:


> In that animation (not actual simulation) the mandibular condyles are displaced laterally and “pushed out” of the glenoid fossae. I don’t think actually happens, it would actually cause TMJ problems but it’s also difficult from a biomechanical point of view (I can’t prove it to you though, but it look like you should first prove what you say).
> 
> To me, condyles act as a pivot point. So, can you imagine the actual widening at the back part of the mandible if the condyles are the pivot point?



Considering that condyles are the pivot point and the chin gets widened, then aren't the gonion pushed inward with a resulting decrease of the bigonial distance after MSDO?


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## Sergio-OMS (Feb 7, 2020)

Gonion said:


> Considering that condyles are the pivot point and the chin gets widened, then aren't the gonion pushed inward with a resulting decrease of the bigonial distance after MSDO?



Mandibular angles are frontal to the condyles. they separate from each other a little bit in MSDO, but just a very little bit.


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## everythingmatters (Oct 7, 2020)

Sergio-OMS said:


> As a matter of fact, as the mandibular intermolar distance increases, a larger amount of maxillary expansion is needed.



Dr, how many mm could the IMW of the lower jaw be expanded with IMDO?


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## Sergio-OMS (Oct 7, 2020)

It really depends on the shape of the mandible and the amount of distraction. Maybe 5 mm widening for 8 mm overjet?


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## Zenturio (Apr 13, 2022)

By what mechanisms does it widen the Bigonial width tho?


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## Zenturio (Apr 13, 2022)

.


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