tips and tricks

Ensure the teeth are relatively clean of food and plaque prior to impressions. I can't count the number of times I have taken an impression and bits of interproximal food come out with the impression. Usually in perio patients and usually in posterior teeth. Really heavy plaque will affect your surface detail capture and food will affect your accuracy and look gross for the lab an on the model. It will also affect your impression disinfection.  If there is really heavy plaque, give the teeth a good prophy or teach the patient how to use a toothbrush and reschedule. If the patient has recently eaten, give their mouth a good rinse and floss. When I haven't done this and there is food that comes out with the first impression, usually the second impression goes well.

Occasionally I have issues with bite registration getting stuck in tooth undercuts in the mouth and being difficult to remove. This is not a major issue as the bite registration usually flexes out or breaks at the point where it is stuck. This can make the bite registration more difficult to handle in the lab stage but is not a big problem. This is becoming especially common as I have switched to a more rigid bite registration material which makes it easier to trim and introduces less inaccuracy during mounting as the material won't deform as much under compression. Watch out for situations where there are multiple non adjacent missing teeth especially with kennedy class 3 situations with bounded saddles. Also kennedy class 4s can be an issue  with especially canines having deep mesial undercuts. Every denture aspect is improved in kennedy class 3s but the bite registration is made more difficult. In class 1 and 2 situations will flex out but 3 and 4 will get locked in. Try not to ...

The issue with directly made temporary crowns are that the bisacryl materials are in general too accurate and once cemented, the lack of space under the crowns means that the temporary will always be seated high due to the hydraulic pressure on the cement. This is why when you are checking the occlusion with the temporary crown dry, everything may seem okay but once it is cemented there is usually a fair bit of occlusal adjustment required. The problem is amplified with thicker temporary cements such as eugenol based cements e.g Tempbond as the film thickness is extremely thick and it will be difficult to flow out as you seat the crown down. You may find that excessive occlusal adjustment leads to thinning of the crown and with conservative preps you may perforate or have frequent crown breakages during function. One strategy to overcome this is to use thinner cements e.g Durelon polycarboxylate cement which is technically a permanent cement. This increases the need to section off your...

It has been countless times that I or the technician have broken teeth off the stone model. Gluing the tooth back onto the model leads to unnecessary fragility and inaccuracy of the model. I am breaking them off less frequently these days but this involves identifying the risk factors for breaking teeth and employing strategies to avoid this occurence. Risk factors: Essentially, anything that introduces an undercut or a thin isthmus of stone.  - Tilted teeth especially proclined or retroclined incisors. Breaking off molars is less frequent as they are short and wide and have less severe undercuts -Teeth with reduced periodontium. This introduces black triangles for material to lock into and increases the undercut as the root diameter is less than the crown diameter. The more severe there perio, the thinner and weaker the root will become. -Triangular teeth: Same issue with black triangles -Porous stone: If the stone is poured with lots of bubbles, the void in the stone will act as ...

A couple of days ago I  left retraction cord in the gingiva of a patient for the first time. Of course it just happened to be my mother. Thankfully, when I put in cord retraction cord, I am very careful to count exactly how many go in and count how many come out. Unfortunately on that day, as hard as I searched, I just couldn't find the cord. It was a small, size 0 cord and was placed quite far under the gingival margin. A mistake I made was not cutting the cord long enough so ended up putting two different pieces to surround a single tooth. The problem was once I removed one piece, I forgot where the second piece started and finished. Rather than continue to dig around the gum, I finished whatever it is that I was doing, brought her back 2 days later and tried again. The gum was not visibly inflamed but the area of the gum that exhibited bleeding on probing was clearly the place where the cord was present. I probed around the gum and found the end of the cord and removed it. ...