Interviewed and translated by Stéphane Renger

Dr Winsauer obtained his degree in general medicine in 1980 at Innsbruck University, followed by four-year clinical training in general medicine and in intensive care. From 1985 he continued at the Dental University in Innsbruck and subsequently received his three-year orthodontic training. Since 1990 he has maintained a private practice with his son Dr Clemens Winsauer in Bregenz, Austria. Dr. Winsauer is a part-time instructor at the Universities of Bern and Geneva, Switzerland.

In 1998 he was the first Austrian orthodontist in private office to pass the European Board examination, since when he has been an active member of the European Orthodontic Society. Dr Winsauer is author or co-author of 17 peer reviewed publications and of four orthodontic textbook chapters. He held the pre-congress course and was keynote speaker at the EOS symposium 2017 on mini screw assisted maxillary expansion in adults. Dr. Winsauer has given numerous international lectures and holds eight international orthodontic patents. In 2021 he is invited as keynote speaker at the AAO (Boston) on the above topic.

He has undertaken scientific research at the Dental University of Graz and the International University of Catalunya, Spain. His main research interests are: maxillary expansion in adults without surgical assistance (moment/force quantification), orthodontic treatment with bone-borne anchorage and mandibular midline distraction osteogenesis.

Interview : 

Stéphane Renger : “Dr Heinz Winsauer, You will come on 21 May 2021 to France for our “next meeting in Lyon, for the 100 birthday of our Society SFODF” 92e REUNION SCIENTIFIQUE DE LA SFODF “100 ans d’innovations en orthodontie au service de nos patients” It is a great honor for us that you accepted this invitation in order to share your experience with the  orthodontists of our SFODF Association (French Society of Orthodontics). Before this event, we are happy to exchange together some aspects of your work and btter know who you are.”

SR : Dr Winsauer, could you explain to us your career path

Heinz Winsauer: My father is a mechanical engineer and I learned through play at a very early age to be able to imagine things in three dimensions. When I was 15, I had already installed a small petrol engine on my bike myself. After I first studied and completed general medicine, I was interested in dentistry as it was more practical. Orthodontics was the subject where I could combine imagination and manual dexterity.

SR: What was the triggering event for you to decide on making a career in orthodontics?

HW: During the orthodontic lectures at the University of Innsbruck, I kept making suggestions on how certain problems could be  solved in a better way. In this regard, I amazed Professor Richter so much at the time that he immediately offered me a training position in orthodontics.

SR: What motivates you to be so active in your profession?

HW: “Changes begin in our minds. If you manage to dream of something that you can hardly imagine, you will get something that you could never have imagined! ”This sentence has accompanied me throughout my life and our world is full of positive changes. Our profession is of course not excluded. New materials, new techniques, new approaches. It is usually harder to forget things and thus to allow something completely new in our lives. We have one of the most beautiful jobs in the world.

SR:  Mini screw implants have become very popular among orthodontists. When appropriately used, they improve the quality of treatment and open up new treatment alternatives. What do you know about the success rate?

 Nevertheless, it has been reported that the failure rate of the mini screws range between 13,5  and 16,4% (two systematic reviews of Paulson and coworkers, and Schatzle and coworkers).

I guess your success rate is much higher. Could you please give us, on the base of your expertise, some advice to improve this success rate?

HW: This article dates from 2009 and compares the palatal implant with miniscrews in the anterior palate. Most of the miniscrews studied in it were between 6 to 8mm long and only about 1.2mm in diameter. This is likely the reason for the high loss rate. In 2017, Hourfar and coworkers found that 98.4% of these miniscrews were secure and stable in the anterior palate, so only a 1.6% loss rate.  This is consistent with my experience. Since about 2013, the length and diameter have increased. I mostly use 14-16mm long and 2.5mm diameter screws (Jeil Medical, DualTop Jet Screw). Most important for success is the so-called “15° rule”: i.e. with M4 position 15° to cranial and buccal and with 15° to distal. For the M5 position, 15° upward outward and 15° from distal to mesial (See the following figures).

In addition to the “entry point”, the inclination for the insertion of mini screws is also very important. The angle when looking from the front is approx. 15 ° upwards and outwards for both M4 and M5. (here a 14mm Dual Top Jet screw at the entry point M4 and M5).

SR:  Concerning the primary stability of mini screws, the bone-implant contact is the key point, but do you think that mini screws are partially osseo-integrated?

HW: Yes, I am firmly convinced that mini screws osseointegrate. However, thanks to their smooth surface, they cannot be retentively surrounded by bone cells and are therefore removable. There are studies showing that new bone even forms along the titanium miniscrews, for example in the maxillary sinus. I never pre-drill in the upper jaw either! It was also never necessary with over 7000 miniscrew insertions. This results in significantly better primary stability. However, one thing is certain – the longer screws are left in the mouth, the less likely they are to become loose. We leave some screws in for five years or more. If the head of the screw does not touch the gingiva, we never see gingival infections. In addition, a smooth screw without a thread in the gingival area significantly improves the prognosis.

SR: How long do you wait after surgical insertion before using them as an anchorage in your treatments?

HW: A mini screw should never be left unloaded in the palate after setting. We connect these directly to the treatment device or glue 2 pieces together in order to obtain secured (secondary) bone stability after 3 months of healing. This is strictly observed, especially in the case of palatal enlargements in patients over 18 years of age.

SR: Ideally, mini screw implants should be designed to enhance their holding in the bone. “Design is not just what it looks like and feels like. Design is how it works” said Steve Jobs. What kind of design of mini screws do you usually use?

From a biomechanical point of view, some of the mini screws you use, like the mini screw from Jeil-Dual Top for example,  have a very long neck. Is it for a better biocompatibilty with the soft tissues?

How do you manage the cantilever forces delivered to the bone (because a long part of the length of the screw is out of the bone)? Is it still comfortable for the patient?

HW: All mini screws that I use are Jet Screws (Jeil Company, South Korea). They have a threaded section of only 7 mm. The upper part of the shaft is smooth and therefore does not irritate the gingiva. I really don’t see any reason to have threads in the gingival area. Today I know why I had chronic irritation at precisely this point, when I used earlier screws with the thread reaching up to the head. This also gives us the option of setting the mini screws more vertically (15 ° rule). A substantial part of the upper shaft can stand freely into the oral cavity, the tongue is not irritated (see picture). The lengths of the Jet Screws vary between 12 and 16 mm due to different lengths of conical shafts. A larger diameter (2.5 mm) guarantees more bone stability, i.e. H. ideal for maxillary expansion.

SR: How do you evaluate the length (in bone and in the soft tissue) of the mini screw before insertion ? In which case do you estimate that a CBCT is needed?

HW: In mixed dentition I usually use 12 mm length, in permanent dentition always 14 mm. In quite a few cases, however, also 16 mm. We use the injection needle as a length measuring instrument. Because the gingiva is crossed diagonally (usually 15 ° insertion angle), 5-7 mm of bone depth must be added to this length (see picture above). However, it is important to always choose the longer screw in case of doubt. Inner feelings (= fear), would rather choose the shorter one.

Regarding CBCT: I didn’t have a CBCT in my own practice for the first 5000 mini screws. At that time I always studied the panorama x-ray carefully! The greatest dangers are hyper pneumatic sinuses and misaligned teeth. An oversized sinus can also be seen on the panoramic x-ray; the maxillary sinus usually ends distal to the first premolar. If this is not observed, there is a risk that the mini screw will be inserted directly into the maxillary sinus as if through an eggshell. Palatally displaced teeth are also clearly visible on the OPTG. In a side comparison, this tooth germ is always larger than on the opposite side. A sure sign that it is breaking through in the palatal direction. Now that I’ve got my own CBCT, I’ve seen a lot, a lot more than ever before. In difficult cases in particular, it helps me to securely place a mini screw or not to start the process at all. I am currently collecting cases for later presentations with the aim of comparing an OPTG with the associated CBCT. Amazing what comes out there.

If the “15 ° rule” is adhered to, mini screws can in most cases be set without any problems, at least in the M4 position. 

SR:  Do you use mini screws in most of your cases? What is the percentage of cases you use mini screws in young patients and for adults?

HW: At least in many. We collected the percentage three years ago: 68% of adults (18+) and 61% of 6-18 year old children and adolescents. The reason for this high percentage is that we do very little extractions. The distalizers are very reliable, work without cooperation, are invisible and it corresponds to today’s time to spare body substance! Another reason for their frequent use is the possibility of correcting midline shifts in the upper or lower jaw in isolation without any problems. Maxillary expansions are now almost exclusively carried out with mini-screw expanders from the age of 7. Especially in childhood they prove themselves very well, they are small, invisible, do not hinder speech, extremely hygienic and can easily be left as retention for 2-3 years. During this time you can always re-expand if necessary. Much, much easier than retention plates, that don’t fit forever or get lost and cause bad mood and arguments, if we have relapse. When I have treated several children from the same family before, numerous mothers have asked me why I didn’t use this technique already on their other children as well.

SR: You have developed different  patents in orthodontics: could you tell us more about them?}

HW: My first patent was a torque measuring wrench and a torque bending wrench to be able to bend third order bends between two brackets and to measure their size. This was followed by a small mirror (Reflex Communicator) mounted in the operating light. You can also fold it away. This makes it easy to explain things to the patient during treatment or to tell them where they should clean better or place elastics. In the early 2000s the Flex Developer was developed as a class II pushing mechanic with an indestructible and resilient polyamide rod and in variable length. It can generate  forces of up to 600 cN and can therefore correct class II very quickly. The sister device was the Herbst Developer, a telescopic tubular construction that can be linked directly to the braces. This means that severe class II dysgnathic cases can be treated by induced mandibular growth in 6-8 months. Another device is the “Tiger-Mini Mold”, a special silicone mold to form bite ramps. Up to 10 mm long, nicely shaped upper anterior bite blocks can be produced precisely next to one another. The Piggyback-Spring is a compressed  coil spring, that can be clamped onto the treatment arch any time during treatment. It pushes teeth apart powerfully. One of the most important patents was a mini screw-supported, re-adjustable compression device, the TopJet, which can be installed chairside in 5 minutes. The device reliably pushes posterior teeth several millimeters distal, invisible and without patients compliance. This means that many premolar extractions can be avoided with it. Another patent was a bondable collar, with which various devices such as MICRO-Expander can be securely but detachably attached to the head of a mini anchor screw (Jet Screw). With the Tiger PowerScrew, a double telescopic Hyrax screw has been developed for expanding the palate, which can be opened and checked by the patient him/herself using a coded hexagon nut. Important people who supported me in the development of these orthodontic devices were above all Prof. Dr. André Walter (Barcelona), as well as my two sons Julian and Clemens Winsauer and my wife Kamila. We are currently working on the development of a completely new type of mini screw system that makes it very easy to use prefabricated expanders and other devices. All of these devices can be viewed at www.tigerdental.com.

SR:  You showed us a new pure bone borne orthodontic mini-implant supported expander for the maxilla with a power screw designed to control the force used. 

Your advice is not to exceed 500cN in your expansion protocol: could you please explain which are the factors who determine this limit and if this amount is the same for every patient whatever their sex or age?

HW: All of the Hyrax expanders’ activation protocols currently known to me require continuous opening of the expansion screw until the expansion target is reached, or – in adults – the expander deforms and / or shows significant side effects. Initially, the MICRO4 expander was also opened in this way. Here, however, it became apparent that due to the extremely rigid construction of the device and the direct transfer of force to the two halves of the jaw, there is an enormous potential risk from excessive forces. Since the activation takes place with an 8 cm long fork wrench, we also use the expander as a force measuring device. The possible activation force at the end of the key is measured using a spring balance and must not exceed 500 cN (gr). Measurements at the Universidad internacional de Catalunya by Dr. André Walter have shown that this value speaks of a spreading force of around 110 Newtons. We did not notice any side effects on the patient or any deformations on the device. A work by von Mao (J Dent Res 2002) on the difference between constant stress and changing stress on sutures inspired me to use a police-cyclical shooting protocol. Since then, we have seen adults (no matter whether men or women up to 50 years of age) have an over 80 percent chance of success of being able to perform the required enlargement without surgical support.

SR: You suggest that a force controlled with a polyclic activating protocol during the maxillary expansion is ideal to open the suture: is this protocol mandatory for all patients?

HW: Yes, this protocol is mandatory for all patients older than 15 years. The patient may not turn more than one side (= 0.17mm) per two days, even when below 500cN.

SR: Do you think that  force control during expansion help to have better success to open the suture of the maxilla? 

I believe that the politics of southern opening and closing is more responsible for success. Limiting the magnitude of the force is a safety measure.

SR: What if there is no diastema after 7 days of expansion and what is your decision if the suture doesn’t open at all?

HW: For the first 7 days, the screw is continuously opened at 0.35 mm per day (two sides of hex nut). If after a week a diastema shows at the check-up appointment, this is encouraging and suggests a simple course of treatment. After this week, every patient, whether diastema or not, must begin the FCP protocol. In one patient, the enlargement of the upper jaw proceeds continuously, in the other we allow 3-4 months for the FcP protocol. In most cases the suture matures and then suddenly begins to open! Patients who feel pressure sensations in the area of ​​the root of the nose, the zygomatic arch and below the nose when opening and closing are called “responders”. They have a very high probability that the expansion will be successful. Patients who do not show any such signs, receive an upper jaw osteotomy after 3-4 months and can then be widened with the same MICRO4 expander (SARPE).

SR: Age is a limiting factor for conventional RPE. In a study from Betts, Vanarsdall and coll.  you showed us during your last virtual conference (continuing education course for our Society SFODF), 79,3% of 487 german orthodontists find that 19,3 years is the limit. 

Expansion could only be done with surgical assistance…

-What is your opinion?

-Is SARPE the only solution for adult patients? Or do you think that hybrid expansion, MICRO2 or MICO4 could be an option of treatment before or instead of SARPE in these adult patients?

HW: As I mentioned above, the chances are very good up to about 34 years of age. Until then the probability is really very high, that no surgical support will be required. After that, the chance of success decreases. In my opinion, an attempt to expand should be undertaken in any case, as there are almost no side effects to fear with this device, provided the rules are respected! I believe that we can save many patients from such an operation and achieve great success as orthodontists (nice appearance through a bright smile, providing space without tooth extractions, improved nasal breathing, no more snoring at night …).

SR: Which are for you the better anatomical signs or classifications that could help the orthodontist to determine if the suture is still active for adult patients (for a good pronostic before expansion)?

HW: Angelieri and Cevidanes (2013) have described a staging of the midpalatal suture into five progressive degrees of ossification in the CBCT. We have been following this classification for a long time and cannot really differentiate between simpler and more difficult cases as part of our expansion. They themselves emphasize in their article that this classification should not be used for diagnostic purposes. Through continuous opening and closing, sutures also seem to form anew. This is also confirmed by my surgeon, when he nevertheless finds a slightly vertically open suture in all patients without diastema intraoperatively in the anterior nasal spine (figure left). I have also observed this phenomenon in the mandible during median mandibular distraction. Here, too, after several weeks of lateral traction on the two halves of the lower jaw, a median suture is formed that is actually not described in anatomy books (figures right). Here, too, the surgeon can cut the lower jaw halves in the upper quarter with a scalpel.

SR: During maxillary expansion, are the amount of force and protocol the same for  traditional hyrax than for hybrid hyrax (hyrax associated with 2 mini screws used for your MICRO2 expander) and for your MICRO4 expander (appliance with 4 mini screws)? 

-What kind of dynamometric  instrumentation do you use to measure the force applied?

HW: The same FCP protocol can be used for expanders such as MICRO2 or hybrid expanders, which are anchored on two mini-screws, but with an upper force limit of 250 cN. To do this, we measure a spring balance on pressure at the end of the activation wrench (Photo)

SR: You showed us excellent results for patient with transverse problems. I am sure you use them often to correct a lot of different anomalies in the vertical or sagittal dimensions also, and you will show us a lot of clinical cases and applications during your next conference in Lyon.

But do you also use these skeletal anchorages  for dento alveolar distractions? For bone stretching methods if ankylosed teeth for example?

HW: Mini screws in M4 and M5 position are also good for mesialization, when lateral incisors are absent or molar intrusion. I’m very thankful for your kind invitation to the conference in Lyon and I will present lots of 5 to 10 minutes chair side simple but real effextive mini screw applications. Today I would  say: “if somebody would stop allowing me the use of mini screws, I would probably not want to do orthodontics anymore”.

SR: Do you always the mini screws yourself or do you sometimes  delegate it to surgeons?

HW: I place all our mini screws myself and ever since I use the CBCT along with it, it has become really simple. It is the same effort as placing a bracket. In terms of a medic: It is a bit like giving an injection.

Do you think that new technologies like mini screws, could explain the decrease of the percentage of orthognatic surgery? Do you think that we could have also better results than orthognathic surgery in some specific cases?

We definitely see less surgery needed. But what we realize, is that we hardly need extractions anymore. A great example is the French Orthodontist Dr. Garnier. He was told, that his daughter would need surgery in order to widen the maxilla. In Paris he heard of this non-surgical expansion technique and came to a course in Bregenz together with his daughter. There we inserted the MICRO4 expander, the crossbite quickly corrected and she finished with a beautiful and stable result. Ever since he has done hundreds of expansions with MICRO2 and MICRO4 expanders.

SR:  Which are for you the most challenging cases in orthodontics in your practice?

HW: Number 1: open bites. Their reason are soft tissues and habits. Things that are quite difficult to influence. Number 2: Impacted canines. The treatment is usually longer than three years, if you finally include a correction of the root inclination. These two take a lot of energy from patient and doctor.

SR:  What are your actual projects or research topics?

HW: We are testing a totally new mini screw system that allows the immediate placement of various appliances chairside and “out of the box” (no lab). The second is a new simplified and low-cost distalizer/mesializer also inserted in minutes without lab.

SR: How do you see our profession in the future ?

HW: Very bright! I think we have the nicest job I can imagine. Three years ago it was the number one profession in the United States. We create beauty without scars and give our patients self-esteem. At the same time we have good communication with them and even full timetables in COVID times.

SR: Thank you so much  for this interview.We are looking forward to listening to you in May during our next meeting in Lyon, for the 100 birthday of our Society SFODF   ” 92e REUNION SCIENTIFIQUE DE LA SFODF

“100 ans d’innovations en orthodontie au service de nos patients”