Orthognathic Surgery - Science topic

I used SpaceClaim from ANSYS to detect errors and correct them.

Thank you very much sir for your reply

Dear Colleagues

Going back to the basics, we all know about the buttresses system of the maxilla.

thinking in that way supporting the osteotomy area at the zygomatic buttress is very logical and that's why we put plate their.

Bone healing is a biological rather than a mechanical. With preservation of the periosteum, a small gap (not 1 cm ?!?) with heal usually.

That's for the advancement and impaction and some rotation of the maxilla, but going for lengthening the maxilla is another story. We know that it is the most ( or second most) unstable movement in orthognathic surgery. Bone graft is some what essential to decrease the relapse rate.

usually we can get some autogenous bone during osteotomies and removal of interferences and we usually crush that bone and added to the gap area ( if not enough we mix it with some xenograft)

For the last 2 years i only put "Lefort I Plates" which only fixed on the anterior maxilla and "FEELS" it is advisable to graft the gap at the "Not Fixed" zygomatic buttress.

regards

CBCT images might be obscure due to streaking artifacts.

Dear Dr.Bassam , i recommend you to read those 2 articles:

1- Analysis of trigeminal nerve disorders after oral and maxillofacial intervention

2- Clinical Evaluation of Peripheral Trigeminal Nerve Injuries as Dr.Salwan recommends

Best Wishes

Hamza

Thank you all for your input. In cases of severe end-stage condylar resorption in adults I personally would recommend total joint reconstruction since it is the most predictable treatment and biochemical pathology would not affect the alloplastic joint. On contrary if it is a stable case of condylar resorption, orthognathic surgery is something I consider (especially if patient declines total TMJ replacement) but I inform patient about chance of relapse. Studies on only Orthognathic surgery as treatment have shown high rate of relapse. Dr. Larry Wolford's papers do support concomitant TMJ surgery and orthognathic in certain cases of resorption.

Dr. Valladares-Neto: I do not know of a standard drug protocol, only protocol published (Level IV evidence) is the one by William Arnett. I do not have personal experience with this.

What would you guys use as a tool to study activity in the condyle? serial cephalometry? serial clinical exams? Tech-99 bone scan? I usually use serial exams/cephs and if there is uncertainty I use Tech-99 bone scans to support.

It would be interesting to see more answers to our question.

Considering the histological studies, usually 3 to 4mm is enough

No idea

Dear doctor, transgingival collar technically means the neck region , so as part of geometry of miniscrew, it governs primary stability. But it is also the region where peri-implant mucosa attachment occurs and is the most vulnerable site for bacterial invasion in case MSI- gingiva interface gets compromised due to peri-implantitis , thus affecting secondary stabililty.

Yamaza T, Kido MA. Biological Sealing and Defense Mechanisms in Peri-Implant Mucosa of Dental Implants. In Tech. Implant Dentistry – The Most Promising Discipline of Dentistry 2011:219-242.

@ Hadrien Bonomi Dunoyer :- Sir, I am talking about  class II patients. 

As per literature approximately 88% of all facial growth ceases by the age of 15 years in girls and 17 years in boys..1,2

1. Broadbent BH Sr, Broadbent BH Jr, Golden WH. Bolton standards of dentofacial developmental growth. St. Louis: CV Mosby; 1975.         [ Links ]

2. Van der Linden F. Facial growth and facial orthopedics. Surrey, UK: Quintessence; 1986.   

Fixed functional appliances like FORSUS are given at approx 14  yrs of age as complete set of permanent dentition except M3 erupt by that age.  

So why not to treat the patient by surgery instead of functional appliances if surgery turns out to be beneficial in terms of airway and skeletal changes.

1. first distraction osteogenesis, then management of ankylosis. this protocol has already been published and offers many advantages . if you follow the opposite sequence you run a greater risk of recurrence of the ankylosis. 2. in this cases i use custom made biomet total joint prostheses which can support a repositioningf the jaw. that has already been published by anders westermark  and works very well. you can plan the operation in a web meeting with VSP  3D planning and you must follow a mandibular first sequence. it works very well and we have done several cases in torino university with satisfactory outcome. similarr methods have been published by wolfed and decoleta.3.tmj hyperplasia:if the hyperplasia is still active we perform condylectomy and orthognatic surgery in a single step in the adult patient, while in the pediatric patient we do treat the condyle and then we wait. If the condyle is not active anymore ( no overgrowth, bone scintygraphy or pet tc negative) we just do orthognatic correction and very often no joint treatment. for condylar resorption , in case of tmj surgery , refer to answer no.2.

i appreciate dr murdoch answer but we always treat bone ankylosis and tmj total reconstruction in a single step with virtual planning and custom made prostheses. these works very well,with great predictability ,good outcome  and 0% recurrence rate of ankylosis. our case serie is going tone published in a few months.

i hope it helps 

kind regards

giovanni gerbino

This question needs additional data. Do you mean a fresh comminuted fractue, non-union or infected non-union ?

In fresh fractures with butterfly or segmental fragment, these separate ( usually with interrupted blood supply ) fragments should not be removed and they usually heal. In non-union and especially in infected non-union the devitalised fragments hamper healing and they should be replaced by vital autografts (not allografts).

In one of our unpublished studies , we found that infrared application without functional appliance retarded mandibular growth but with insignificance difference from the control group. We couldn't publish it because of the sample size. 

1. mandible first approach 

2. multisegment Le Fort for width control

Thanks Vijay and Henry. But is it worth doing orthognathic surgery in patients already on long term  bisphosphonates? Not patients due to start bisphosphonates. The patient has been on IV bisphosphonate for 7 years.

Decision of surgical first approach depends on the severity of skeletal malocclusion (class II or class III) and the time constraint. Based on the pre-treatment Incisor inclinations in Moderate-Severe class II or class III, I assess the amount of dental de-compensation required through an extraction/non-extraction approach.I prefer non-extraction approach in a skeletal class III and extraction in class II cases. Incisor inclination influences the outcome of any orthognathic surgical procedure.

Proper pre-surgical orthodontic preparation and accurate surgical planning are essential in order to achieve optimal results in orthognathic surgery. This necessitates a close working relationship between the orthodontist and the surgeon as a part of a comprehensive multidisciplinary team.