Day 3 observing private practice prosthodontics

 Today I spent another day at the prosthodontic practice. It was a pretty packed day with a mixed bag of treatment, some cases just starting, some far along both surgery and fixed prosthodontics.

-Bonded gold restorations lower canine buldup: The patient had a history of bruxism and had worn teeth. The anteriors had been restored as veneers in composite resin and the patient requested a gold restoration for the upper right premolar. The preparation was essentially a veneer with a buccal path of insertion. The veneer wrapped around over the buccal cusp with the finish line at the position of the cusp tip. It extended equigingival and mesially and distally between the line angles and the contact point, just far enough to mask tooth structure. In the middle of the facial surface there was a round 0.8mm diameter dent prepared into it for resistance form. The temporary restoration was a shrink wrap bisacryl which was locked into the interproximal undercut. There was an enamel chip on the 34 buccal cusp that was restored in gold by preparing a "dagger shape" into enamel which was a mesiodistal slot on the occlusal aspect of the buccal cusp, a buccolingual slot running from this from the central fissure and running onto the buccal surface to encompass the fracture. The bonding was done with relyx ultimate automix syringe. The restoration was tried in on a dry tooth, gold is good because if there is any imperfection of fit it can be burnished at the margins. An adhesive microbrush was used to handle the small repair restoration as it was difficult to handle. The gold was dried, tooth was etched for 10-15 seconds, dried and scotchbond universal was put on the tooth and restoration and air dried but not cured. RelyX ultimate was extruded in excess onto the tooth and restoration and the restorations were seated firmly. Excess cement was removed with a microbrush in a wiping action at the margins. A thin and long tipped microbrush was used to clean the interproximal and the edges were cured fully. The microbrush is used to remove excess cement but a thin amount will remain which is removed with a bur below the margins. Ideally try to start with a yellow diamond to remove the cement because it will leave smaller scratches that are easier to polish away later. If some adjustment of the restoration is required though, a red diamond flame shaped polisher was used to ensure the restoraiton was flush with the tooth then a yellow, shorter flame tip was used to polish this. A green tubber polishing tip was then used over the whole restoration then a pink rubber spiral wheel with a yellow centre then cosmodent diamond polishing paste in a prophy cup was used to give the final shine. Articulating paper was ineffective in marking the gold so the opposing tooth was checked and both the gold and opposing composite resin was adjusted because the opposing canine was too steep in its disclusion. The lower canines were built up slightly after this to increase the canine disclusion of the posteriors because they were in group finction leading to wear of the posterior teeth. Building the upper canines is somewhat effective but usually only serves to increase the steepness of disclusion. In contrast, building up the lower canines has a more immediate, more potent effect in causing posterior disclusion. The aim is to fit bonding material to make the lower canine taller but not to disturb the centric contacts that were formed in the previous phase of treatment. This involves adding composite resin to the areas incisal to that of the centric contact. As the jaw moves into lateral excursion, the occlusal contact will move from the centric contact towards the incisal edge. The surface was roughened with a red diamond football bur, etched, bonded and composite resin was added using modelling resin to improve handling. Modelling resin was applied to the opposing teeth and the patient was instructed to close and tap together using the opposing tooth to reestablish the centric contact. Then the composite was reshaped into an incisal edge and cured. The bite was checked to ensure that centric contacts were not disturbed then excursive contacts were checked and reduced it guidance was too steep.

-Records appointment: The patient had a consultation with the prosthodontist last visit and had returned for record taking. He structures his appointments with an initial meet and greet, finding out their main concerns and where they want to end up and giving a vague idea of costs and possible treatment options. He then has them return for a records appointment where he has more of a conversation, takes photos, intraoral scans and xrays as required. The patient will bring in any old photos of themselves if applicable. Even at this point he doesn't promise any particular treatment option but instead says he will wax up and plan the case to give them an idea of what it will look and feel like before they commit to anything irreversible. He starts with photos: with him and the patient standing, he takes frontal face at rest, face smiling, 90 degrees face at rest, face smiling. He sits the patient down, takes close up face at rest, close up smile. He then puts an optragate in for retraction, takes teeth together, teeth slightly apart. Lying the patient back and without changing the focus,  he holds the occlusal mirror in his left hand and the camera in his right taking the maxillary and mandibular occlusal photos. The photo he always forgets to take is the retracted full face photo which gives an idea of how the maxilla relates to the occlusal plane. For the scan he uses the itero system and has the patient holding the high speed suction at the opposite side of the mouth to bring the humidity down to avoid fogging the sensor and uses triple air to dry the teeth before the scan.. He scans the mandiblar arch then maxillary starting with the occlusal surfaces from one side to the other then moving to the buccal surfaces going the other way then moves to the lingual. He doesn't move on to the next tooth unless he has gotten an appropriate scan. If there are any spots which are still missing at the end he goes back and tidies them up. The difficult areas are the buccal areas which he gets the patient to half close to allow access to them. The bite record is taken in MIP and both sides of the arch together are required to take the bite. The second bite he takes is with a leaf gauge. He puts the scanner down for a few minutes and puts the patient in a leaf gauge. If the patient keeps letting go he tugs on the leaf gauge and says "I shouldn't be able to pull this out". he makes the patient retrude and squeeze. The patient holds there and should start to feel some tightness around the tmj area after a few minutes which is the lateral pterygoid stretching out. after a few minutes he gets the patient to relax their bite then bite down to stretch it out more. This gives an estimate of centric relation and the bite is taken at the approximate opening when he wants the vertical dimension should be. Once the second bite is taken, he removes the leaf gauge, manipulates the jaw into closing till first contact. The difficulty in getting the patient to relax the jaw and allow manipulation gives the idea of how constricted the muscles are and gives an idea of the need for deprogramming. By this point the patient can feel the imbalance in their jaw and as he explains it "there's no point doing all the work and finding out the jaw was in the wrong place. We want to find out where the jaw should be and restore things there." He then shows the patient the photos and scans and gives them an idea of the treatment objectives, not how they will be achieved e.g make teeth longer, moves gums upwards, replace teeth. Gives some instructions on how to use a bite tab (cut op square of mouthguard material to stretch the lateral pterygoid and also instructions on how to stretch the masseters my forcing the  mouth open with the index fingers. He takes a copy of the old photos for the lab to do the wax up. In this case the patient also wanted whiter teeth and he explained that whitening would be the first step to see how light they could become. He explained that if she wanted teeth whiter they can either be bleached or covered i.e veneered.

-Issue implant crowns: The patient had a missing 14 and 15 replaced with implants and they were being restored with splinted implant crowns. He uses the biohorizons system and the splinted crown abutments are designed as engaging with a conical shape at the occlusal aspect of the implant interface and a hex at the base. The enaging hex part is designed to be used with "screwmented" crowns which are porcelain crowns with a screw access through it and is cemented onto the abutment. As implants can never be perfectly parallel, the engaging hex must be trimmed back after fabrication and cementation of the crown in the lab. In this instance the lab had trimmed it back on the mesial and distal apect but hadn't done so on the buccal and lingual. This was an issue as the implants were placed at a tilt buccolingually relative to each other and the crowns weren't seating. This meant that they had to be adjusted chairside. He got a cone shaped diamond bur with a flat end and rounded off the hex surface staying slightly away from the conical section. The very coronal section of the hex was retained to allow retrievability of the crown. If there is a debond of the crown off the abutment, the lab can recement the crown but they need a way to locate the abutment onto an analogue as there is an infinite number of positions a conical connection can rotate around an analogue whereas a hex is limited to 6 positions. Once the screw is tightened, the conical connection is enough to support the crown and the hex is only needed if there is an issue with the crown down the line. He has recurring issues about the design of implant crowns from his lab. To design the emergence profile, the lab pours up the gingival area with soft tissue substitute which can be trimmed back to design the shape of soft tissue. The issue with lots of labs is that they trim back the soft tissue too excessively not understanding that there is bone underneath that will be compressed which a lot of effort has gone into to preserving. Overtrimming of the soft tissue in the lab will result in compression of soft tissues, can prevent seating of the crown and can cause significant pain to the patient. The emergence of the crown in a deeply placed implant should be fairly vertical and widening out when there is no bone around it. If there is recession exposing the narrow neck of the crown then the crown can be removed and more porcelain stacked on top. Compression of the tissue due to the insertion of an implant crown moves fluid out of the tissue and takes time for the fluid to flow so the crown is inserted incrementally with a the screw tightened a bit at a time with a few minutes of rest in between. The patient is warned they may feel a pinching sensation. After a few turns, getting the patient to bite down on the crowns with a cotton roll can help to apply pressure to the tissue. He usually just screws the implant crown down to the right torque and reviews it down the line without a same day xray unless something doesn't seem right. In this case, the bite was high on the crowns which indicated to him that the crowns weren't seating fully. he took a PA and noted that the posterior crown was not seated. He adjusted the hex as previous discussed and it seated a bit more. However, it was the over trimming of the soft tissue in the lab that was holding the crowns up on the surrounding soft tissue especially the interseptal soft tissue under the splinted crowns which meant that the crowns were difficult to seat fully as well as difficult to clean as an interdental brush wouldn't fit underneath. He got a hint of the difficulty seating with a "aquishy/squeaky" sound when screwing down the crowns. This sound is the friction of the flat part of the screw head against the flat part of the abutment. Usually when this sound is heard, there aren't many more turns of the screw possiblr before the crown is fully seated and the torque increases. In this case, the squeaky sound was heart quite early and the screw continued to be able to be turned as the crown seated more. This indicated that there was something holding up the crowns which increased the friction of the screw head against the abutment and that the abutment wasn't fully seated. If this is soft tissue or bone holding the crowns up, the screw can loosen either due to tissue resorption or just because it isn't possible to tighten it properly so he will come back in about 6 weeks, open the access and retighten the crowns. Another recurring issue is the lab making a mistake in the bonding steps. The crowns are cemented onto the abutment with RelyX resin cement and if the lab forgets to do the bonding steps properly e.g forgetting to add bond then the crowns will debond before too long.

Gingivectomy: This patient was an aesthetic case with high demands. She had completed orthodontics in the upper arch and was still in fixed appliances in the lower. The gingivectomy was part of a bigger plan to level and align everything as well as to improve the texture and colour of the teeth. He planned the gingivectomy from a close up smile photograph taken at the start of the appointment and eyeballed it freehand. The patient had canted gingival marginsso he mainly had to remove gingiva from the left hand side central, lateral and canine and the right hand side canine to balance everything. After giving local anaesthetic, he probed under the gingiva with a sharp explorer sliding it down at a flat angle and once a bump was felt, turning the probe almost perpendicular to the tooth surface and drawing it back up to locate the CEJ. As the CEJ was located above the attachment a fair way below the gingival margin he surmised that the imbalance in gingival margins was due to altered passive eruption and a flap and bone removal wasn't needed however he warned the patient beforehand that this may be required. He said he didn't really use the pupils as a reference point as the lip is much closer and is therefore a better determinant of the aesthetic plane. He used an electrosugery unit with a thin loop tip on a high cutting setting. He used sweeping strokes from side to side with the tip angled at 45 degrees towards the tooth surface pointing gingivally. The high speed suction had to be going constantly to remove the smell. He had to keep moving the tip out of the way as it kept coming into his view. The view of the incisal edge plane and the gingival plane had to be kept clear as he kept referring to these in making the adjustments so the tip sat about the edge of the mouth where the optragate was. As the surgery progressed, he had a wet gauze which he wiped the tip of the electrosugery unit against to remove the tissue stuck to it and wiped the surgical site as well. Therewas no bleeding due to the cautery and I Assume it healed wuite well as the wound was small.

Splint review: This patient had issues with his bite after wearing a full coverage splint. He was a high stress teenager and had suffered from muscle pain for a long time. He had been wearing a full coverage splint for a number of months and now felt as though he couldn't bite correctly. The bite was checked with a leaf gauge and the patient had contact with most of the leaf gauge in. He was opened up out of contact with the leaf gauge and the patient was stress tested by retruding to see if any discomfort could be elicited by stretching the lateral pterygoid and activating the elevator muscles. No muscle pain was elicited by this which meant that the splint was doing its job but as the first contact was at the wisdom teeth, it was assumed that overeruption of the wisdom teeth occured as they were not covered in the splint. To remedy, he planned to extract the wisdom teeth starting with the interfering upper one and possibly the other side if it went well on the day. The lower 8s were in close proximity to the IDN and so he planned to leave these for the moment and consider extraction down the line after overeruption which may pull them away from the nerve. A note on jaw physiotherapy for myofascial pain is that the bite tab exercise is mainly to stratch out and resolve pain in the lateral pterygoid but will somewhat help the masseters and temporalis as although they are activated, they can't be activated to full force without tooth contact. This will theoretically help a locked disc as the deprogramming relaxes the lateral pterygoid which is tense from posturing the mandible lateral and will release the disc. The excercise which helps the elevator muscles is getting the index fingers under the maxilla and mandible pulling the jaw open and stretching the muscle. the only issue is in cases which lock open to be careful and do it slowly.

Resuture appointment: This is a patient who had a sinus lift and bone graft but the sutures had pulled out. In this case he was prepared to replace the membrane and suture the flap back but the membrane was intact and in place so he ended up just suturing the flap back. After anaesthesia, the surgical site was irrigated with ozone water to disinfect it. As the flap had stopped bleeding, he used a scalpel in a scraping motion on the underside of the flap to start it bleeding again to form a clot and encourage healing as bleeding means healing. He sutured the flap down first with a modified vertical mattress suture which etered the middle of the flap, went through the palatal about 5mm away from the edge, went back through the palatal 2mm from the wound edge and through the flap again near the edge. He then looped this back through the loop on the palatal and tied it down with the tail edge. This tightens the flap down significantly but instead of everting the wound edges which would occur with a normal vertical mattress suture, it brings the edges down to approximate the edges and holds the falp onto the bone. He then used simple interrupted sutures to approximate the flap edges. It is important to ask why something has gone wrong and with all his surgeries he has intraoral photos of each step which I think is very useful to easily have a record that can be critiqued down the line to check the technique when something goes wrong. In this case the patient had been constantly sneezing since the surgery and had been experiencing nosebleeds. The trauma of the sneeze and movement of the buccal muscles is probably what pulled out the sutures. Some tips Ipicked up during the suturing were: Hold the tail of the suture tucked under the pinky when putting the initial pass to keep it out of the way. If you leave the tail free it can get tangled or get in the way. After the needle has passed through the tissue, pull it through till the tail is sitting at the corner of the mouth. Tie the first throw and pull the long end only while moving the needle holder holding the tail into the mouth near the wound edge. To keep the knot flat, pull the tail end to the opposite side of where it was before the knot i.e if the needle passes through the buccal flap first then the palatal tissue, the tail will be located on the buccal aspect and when tightening should be pulled towards the palatal. To add extra tension, after tightening, pull the tail back towards the buccal then the palatal again in a see saw motion. After tying the knots, the tail end will be int he needle holder and the long end will need to be held taut to cut. Hold the needle holder so that the tail end is vertically upwards from the wound and drape the long end over the tip of the needle holder to keep them both taut while the assistant cuts the ends. Dry the wound with gauze before applying periacryl with a microbrush and dappens dish that have been kept sterile in a steri bag.

Denture review: This was a patient who was being reviewed after making some adjustments to her old denture. She had been to many prosthetists in the past who were unsuccessful in making her comfortable full over partial dentures. He was the first person who took an xray of the patient and noticed she had a condylectomy many years ago and wasn't even aware of it. The bite was strage due to this as one side was collapsed and there was a very large cant in the bite and abnormal mandibular excursions. To improve the situation he did a soft reline which tends to self correct the bite as the patient's functional movements and chewing balances out the denture. He then converted this into acrylic. The patient's old denture had a clear acrylic base and so they replicated this in the reline but the patient was complaining that there was a strange taste from this acrylic which is likely due to the brand of acrylic used. The idea of the clear acrylic is that it may be easier to identify pressure spots but in reality doesn't really work that well.

Veneer consult: This patient had black triangles due to recession of the gums after periodontal treatment. Black triangles aren't necessarily an indication of periodontal disease but are the results of recession which is exaggerated by the triangular shape of teeth. With triangular shaped teeth, the contact point is high and the gingival embrasures are large so with small loss of gingival height, large black triangles can form. The 5mm rule states that if the contact point is within 5mm of the interseptal bone crest then the gingival tissue will grow and fill the space. The issue with triangular teeth is that the contact point is very high so with the loss of bone, the lack of support will cause gingival loss. By performing restorative procedures to lower the contact point and convert the teeth into squarer teeth, the gingiva can grow and fill the remaining defect if it is located within 5mm of the bone level. It is important to get the patient's periocontal condition stabilised before this is attempted. With periodontally affected teeth, usually the teeth themselves are healthy and unrestored but the periodontium is what is damaged. Therefore in post periodontal treatment, ceramic is less desirable due to the unrestored nature of the teeth and composite resin may be favoured. Asking patients about their staining history i.e tea and coffee is useful as patients who engage in staining habits need to be warned that composite resin picks up stains a lot quicker than ceramic. Another thing to note is that if composite chips it can be repaired fairly easily but if ceramic chips it likely has to be replaced completely. He quotes them in the early consult stage per tooth and gives an idea of how many teeth need to be treated.

Implant crown impression: This patient had an upper central incisor implant placed and had been wearing a temporary crown for a while to develop the tissue. The shape of the tissue was captured with flowable composite. The temporary crown was removed, the impression coping was placed and quickly flowable composite was injected into the tissue site and cured to hold the space. The patient was seeking bleaching to lighten his teeth so the final shade was estimated and after bleaching the crown would be tinted chairside to finalise the shade. A lower tray is used for the impression and a straight handpiece used to drill a large hole for the impression coping to go through. After this, adhesive is applied and dried with air. Automix heavy body was loaded into a syringe then the tray as light body was put around the site, gingival margins and occlusal surfaces of all the teeth. Then heavy body was syringed around the implant site as this is the last place that the material in the tray would flow as the other sites are filled with teeth so all the bubbles would flow to the implant site if not completely filled with impression material. The impression tray was seated and a finger used to wipe the material off the impression coping screw. Once the material wa set, a probe was used to clean material out of the screw and the screw loosened and impression removed. The temporary crown was crewed on with teflon and composite to seal. Shade photos were taken with the whole shade guide with multiple photos at different angles with the shade guide at different angles rotating it upper and lower and with the camera higher and lower to capture different planes of the tooth.

Review implant: The patient was complaining of swelling of the gum and pus draining. It looked as though there were loose graft particles embedded in the soft tissue which would push themselves out on their own and be removed. It wasn't a big deal and when using a metal instrument to tap the cover screw, a metallic, ankylosed sound was produced which is a good sound indicating osseointegration.

Composite veneers review: This patient was quite an exasperated one as part of her composite veneers had chipped which had been repaired multiple times already. The issue was the lower incisors were mildly crowded and the tooth that projected forward was chipping the upper veneers in protrusion. This was repaired by roughening the old composite, bonding procedures and applying new composite resin. One thing that I picked up was to run the soflex disc quite slowly and use the second roughest disc first avoiding the roughest as it cuts too quickly. I run my soflex discs at full speed and often find that I can over cut them or ditch into the incisal edge.

All in all it was a mixed day and I picked up a few good tips. Not sure how many free days I will have left to go and observe but hopefully will be able to drop by again if he is kind enough to let me do so.