Is a return to the explosive growth of the past just around the corner for Align Technology (NASDAQ:ALGN)? Or could the dental medical device company's once high-flying stock experience its most disappointing year in quite a while?

Prior to some good news from an analyst upgrade this week, Align's stock was down more than 20% year to date. That's a far cry from the strong returns from previous years. Whether Align resumes its winning ways could depend on the answers to these three key questions when the company announces third-quarter results on Thursday.

Source: Align Technology. 

1. How lazy was the summer season?
Summer cuts both ways for Align. On the positive side, many teenagers like to start orthodontic treatment in the summer months. When the company reported its second-quarter results in July, things were looking up, with momentum expected to continue through August. 

On the other hand, many North American dentists and international doctors take vacations during those same summer months. That means fewer days in the office to put Align's Invisalign clear aligners into waiting mouths. This slowdown is especially prevalent in Europe. 

Align also makes significant revenue from its scanners used by dentists and orthodontists. However, summer tends to be somewhat sluggish for capital equipment purchases. A big factor impacting how well Align's third quarter went will be whether the summer of 2014 was more or less slower than expected. 

2. Is there still a bull in the China shop?
Asia continued to be on fire last quarter, with no hotter market than China. Align reported that case volume in China more than doubled year over year in the second quarter. CEO Tom Prescott estimates there are between 20 million and 50 million Chinese with sufficient financial resources to be potential customers for Align's products. 

There are at least two reasons to expect good results from China and the rest of Asia. First, many patients in the region have more complex orthodontic issues, making them a good potential fit for Align's Invisalign G5 product. Second, Align is still relatively new to the Asian market -- with plenty of room to grow. 

However, barriers still exist for effectively penetrating that big potential market. A key question for Align will be how well it's overcoming those barriers. The answer to that question could significantly impact the stock's performance in the coming months.

3. How hot is the branding iron?
While Align has been in business for 15 years, many people still have no knowledge of its products. The better the company can build its brand (especially among teens), the more sales it can generate.

Source: Align Technology. 

Align has focused heavily on brand-building recently. The company ran promotions in the second quarter targeting teens and their moms. Those promotions continued into the third quarter. Social media has been a high priority for Align as well. From Instagram to Tumblr to YouTube, Align actively promoted its products to teens over the last several months. 

How effective have those efforts been? Align's third-quarter results could tell the tale -- or at least the beginning of it. Positive early results from the brand promotion campaign could translate to stronger sales and a resurgence in share prices.

The long run
Align benefited from an upgrade from Credit Suisse on Monday, with shares jumping 5%. This more positive view makes sense, because it was all about the long run. Credit Suisse analyst Glen Santangelo said that his company thinks "the still-nascent growth nature of the Align thesis warrants a longer lensed analysis." That's the kind of perspective The Motley Fool encourages.

In the near term, Align's stock's fortunes hinge on how the company answers questions like the three listed earlier. Over the long term, though, success depends on whether Align can continue to innovate and expand its markets. If those questions are answered affirmatively, Align should be as good of an investment choice in the future as it has been in the past.