Why do a mock up?

A mockup is a trial run in the mouth of a functional and/or aesthetic restoration. This can be done in a multitude of ways. Small aesthetic restorations, even mockups for bridge pontics can be done freehand. Models can be take and waxed up to their final form. This may be more time and cost effective when multiple teeth need to be restored. A putty stent can then be taken of this waxup and transferred to the mouth with self cure resin e.g temporary crown material. The question is why is this an important step?
-It is important to get the patient's approval of the aesthetics before the final restorations are put in place. You can discuss finer points of the patient's aesthetic rehabilitation beforehand but nothing is as effective as a visual representation of the possible appearance of the patient's future smile. The best time to find out what the patient likes or doesn't like or if they have unrealistic expectations is before the final restorations are placed and especially before any irreversible procedures are done
-The mockup can be a motivating procedure for a lot of patients who have grown to feel as though their teeth are hopeless. If you can show them that an attractive and functional dentition can be achieved it may allow them to accept treatment plans that they are capable of affording but have been hesitant to commit to due to lack of hope.
-Testing the phonetics and aesthetics i.e the position and form of the anterior teeth is important in treatment planning. The waxup is not always perfect as imperfections can occur in mounting, smile design and transfer to the mouth so it is important to have a trial run to test how the wax and digital planning is going. Minor adjustments can be done that can correct imperfections in the design. An impression can be taken of this direct mockup and can be used as the cast to guide the future treatment. I liken the mockup to a denture try in. In most cases you wouldn't go straight from a secondary impression to a finished product.
-It is important to note that a reductive waxup cannot be tried in. This mean that if the final form of the teeth is not additive, then the putty stent will not seat fully. Therefore you either need to get the patient's permission to cut their teeth to seat a reductive wax up or have an additive waxup done and explain that the teeth will either be shorter or less bulky than the mockup.
-A mockup over the gingiva to represent soft tissue work e.g evening gingival zeniths or crown lengthening can emphasise the importance of the patient of corrected soft tissue aesthetics. Without seeing what things will look like when the teeth and gingiva are in harmony, the patient may elect to avoid soft tissue surgery due to fear of pain or cost or unneeded complexity of treatment.
cant mock up if reductive without cutting
-Mockups can be used to guide the reduction of tooth structure. Depth cuts can be done through the mockup to ensure that tooth structure is removed to the correct amount avoiding excessive removal of tooth structure or underprepping.

Mockups are a critical stage in a rehabilitation for the dentist as it is most commonly the last step before the procedure enters a non reversible stage and it is important from a patient perspective as it provides them with the motivation to proceed with treatment and will keep them motivated for the duration of what is commonly very protracted treatment.d