Last reviewed: April 2026 · Based on current clinical protocols at DenCos, Hoofddorp
Orthodontic treatment is the dental specialty focused on correcting the position of teeth and jaws using appliances such as Invisalign clear aligners or fixed braces. At DenCos in Hoofddorp, all orthodontic treatments are performed by Dr. Jing Guo — a registered specialist orthodontist and Invisalign Diamond Apex Status ranked in the top 1% of providers in Europe, with over 3,000 cases treated.
This page answers the most common questions about Invisalign, fixed braces, appointments, costs, and emergencies. For a complete overview of the treatment process, see the orthodontic treatment journey.
Is Invisalign suitable for me?
Invisalign aligner treatment is suitable for approximately 99% of orthodontic cases at DenCos, regardless of age. Dr. Jing Guo treats children (from age 6 with Invisalign First), teenagers, and adults with clear aligners.
During the initial consultation — which takes approximately 45 minutes — Dr. Guo performs a comprehensive assessment using 3D intraoral scans, digital photographs, and X-rays. Based on these diagnostics, she creates a personalised treatment plan with ClinCheck software, showing the expected result before treatment begins.
For the small percentage of cases where fixed braces are more effective (severe skeletal discrepancies or complex vertical movements), Dr. Guo will recommend the best alternative.
Can I transfer my treatment from another orthodontist?
In most cases, orthodontic treatment must be restarted when switching practitioners. Treatment plans are specific to each orthodontist's clinical approach, appliance system, and treatment goals. According to the Dutch Association of Orthodontists (NVvO), continuing another practitioner's plan without full diagnostic access may compromise the outcome.
During a consultation at DenCos, Dr. Guo assesses your current treatment status — including any existing records or appliances — and determines whether a modified continuation or fresh start will produce the best result.
What are attachments?
Attachments are small, tooth-coloured composite shapes bonded to the surface of specific teeth during Invisalign treatment. They act as anchor points that give the aligners additional grip, enabling more precise and complex tooth movements such as rotations, extrusions, and root torque.
The number and placement of attachments are determined by Dr. Guo using ClinCheck 3D planning software. Attachments are removed at the end of treatment without damaging the enamel.
How often do I change my aligners?
You typically change your Invisalign aligners every 7 to 14 days, depending on your personalised treatment plan. Each new set of aligners continues moving your teeth toward the planned positions.
Key wearing guidelines:
- Wear time: 20–22 hours per day
- Remove for: eating, drinking (except water), brushing, and flossing
- Switch schedule: every 1–2 weeks as prescribed
- Check-ups: every 6–8 weeks at DenCos
Consistent wear time is the most important factor for keeping treatment on schedule.
Can I eat or drink with aligners?
You can drink water with your aligners in place. For all other beverages — especially acidic, hot, or coloured drinks — remove your aligners to prevent staining and warping.
Always remove aligners before eating any food. After your meal, brush your teeth (or at minimum, rinse thoroughly) before reinserting the aligners. According to the American Association of Orthodontists, food particles trapped between teeth and aligners can significantly increase the risk of cavities during treatment.
How does Invisalign compare to fixed braces?
Both Invisalign and fixed braces are effective orthodontic treatments. The best option depends on your specific case — Dr. Guo recommends the most suitable approach during your initial consultation at DenCos.
| Feature | Invisalign | Fixed braces |
|---|---|---|
| Visibility | Nearly invisible clear plastic | Visible metal or ceramic brackets |
| Removable | Yes — remove for eating and brushing | No — fixed for the duration of treatment |
| Treatment duration | 6–24 months | 12–36 months |
| Appointments | Every 6–8 weeks | Every 4–6 weeks |
| Cost range (NL) | €2,500–€6,500 | €2,000–€5,500 |
| Best for | Mild to complex cases | Severe or skeletal cases |
What if there is not enough space for my teeth?
When teeth are crowded and there is insufficient space for proper alignment, Dr. Guo may recommend IPR (interproximal reduction). IPR is a technique that gently removes a fraction of a millimetre of enamel from between selected teeth to create the space needed for movement.
IPR is safe, painless, and well-supported by orthodontic research. The amount of enamel removed is minimal (typically 0.1–0.5 mm per contact point) and does not affect tooth health or sensitivity.
How often are appointments for fixed braces?
For fixed braces, adjustment appointments at DenCos are scheduled every 4 to 6 weeks. During each visit, Dr. Guo adjusts the archwire, changes elastic ligatures if needed, and monitors tooth movement progress.
Fixed braces treatment typically lasts 18–24 months, depending on case complexity. For a complete overview, see the orthodontic treatment journey.
What should I do in case of an emergency?
For orthodontic emergencies during opening hours, call DenCos at 023-792 0463 to schedule an urgent appointment. Common emergencies include:
- A broken bracket or wire
- Severe pain or irritation from appliances
- A lost or damaged aligner
For emergencies outside opening hours, follow the emergency protocol provided at the start of your treatment. For severe pain or swelling unrelated to your orthodontic appliance, contact your general dentist or the dental emergency line.
Next step
Have a question that is not answered here, or ready to start treatment? Book a consultation at DenCos or call 023-792 0463. DenCos is located in Hoofddorp, Haarlemmermeer, and serves patients from Haarlem, Amsterdam, Amstelveen, Aalsmeer, Heemstede, Bloemendaal, Lisse, Bennebroek, and the wider region.