WhatsApp vs SMS for dental appointment reminders: what gets opened?

If you are choosing between WhatsApp and SMS for dental appointment reminders, the decision comes down to more than open rates. Both channels are opened by the majority of recipients — the real difference is in what happens after the message lands. This comparison covers open rates, response rates, two-way communication, cost, technical setup, and the patient behaviours that actually determine no-show rates.

TL;DR

• Both WhatsApp and SMS achieve high open rates (90%+), but WhatsApp generates significantly higher response and confirmation rates.
• WhatsApp supports two-way interaction that reduces no-shows; SMS is largely one-directional.
• The technical setup for WhatsApp Business API is more involved than SMS, but platforms like CodeWords handle it end-to-end.

Open rates: the headline figure that isn't the whole story

Open rate is the most-cited metric in the WhatsApp vs SMS debate, and it tends to paint a misleadingly similar picture for both channels.

SMS open rate: 82–90%. SMS has historically been opened at high rates because the notification interrupts the recipient and the message is short enough to read instantly.

WhatsApp open rate: 90–98%. Slightly higher than SMS, primarily because WhatsApp messages arrive via the same channel patients use for personal communication, which increases the sense of urgency.

The gap in open rates is real but not dramatic. Where the two channels diverge significantly is in what patients do after opening the message.

Response rates and confirmation behaviour

The mechanism by which appointment reminders actually reduce no-shows is confirmation. A patient who actively confirms their appointment is four to five times less likely to miss it than a patient who simply receives a reminder. This is why response rate is a more useful metric than open rate for measuring no-show prevention.

SMS response rate for dental reminders: 15–25%. SMS is largely a one-way channel in practice. Even where practices include a reply keyword (e.g., "Reply YES to confirm"), patients reply at relatively low rates because it requires switching mental mode — from passively reading to actively responding. There is also no indication to the patient that their reply will actually be processed.

WhatsApp response rate for dental reminders: 45–65%. WhatsApp is a conversational channel. Patients are conditioned to respond to WhatsApp messages in a way that they are not conditioned to respond to texts from unfamiliar numbers. When a WhatsApp message includes a "Confirm" or "Reschedule" quick-reply button, the friction of responding is minimal — it is a single tap.

The implication for no-show reduction is substantial. If you send 100 appointment reminders, SMS generates 15–25 confirmations. WhatsApp generates 45–65. The remaining unconfirmed appointments are the no-show risk group. WhatsApp roughly halves the size of that group compared to SMS.

Two-way messaging: the structural difference

SMS is bidirectional in theory but effectively one-directional in practice. A patient can reply to an SMS reminder, but:

• The reply goes to a long or short code that may not be monitored
• Practice staff may not see the reply until hours later
• There is no automated handling of the response

WhatsApp, accessed via the Business API, is designed for two-way conversation. A patient who replies "I need to reschedule" can receive an automated response with available slots, complete a rebooking, and receive a confirmation — all without staff involvement. A patient who asks "What should I bring to my appointment?" can receive an automated answer from Cody, CodeWords' AI assistant.

This structural difference is what makes WhatsApp fundamentally more capable for appointment management, not just appointment reminders.

Cost comparison

SMS per-message cost: Typically £0.03–£0.06 per message in the UK, depending on volume and provider. A three-stage reminder sequence (48h, 24h, 2h) costs roughly £0.09–£0.18 per patient appointment.

WhatsApp Business API per-message cost: WhatsApp charges per 24-hour conversation session rather than per message. Utility conversations (appointment reminders, confirmations) are priced in the region of £0.02–£0.05 per session in the UK. A complete reminder + confirmation conversation counts as one session.

See how CodeWords works for dental practices → codewords.ai/whatsapp-agents/dental

At volume, the costs are comparable. WhatsApp becomes more cost-effective per interaction when the two-way conversation replaces what would otherwise be phone calls from staff — the cost of a receptionist spending 3 minutes on a phone confirmation call significantly exceeds the cost of a WhatsApp session.

Technical setup: SMS vs WhatsApp Business API

SMS setup is straightforward. Most dental PMS platforms have SMS integration built in, or you can add it via a simple API connection. Configuration takes hours, not days.

WhatsApp Business API setup requires more steps: applying for a WhatsApp Business account, having message templates approved by Meta, verifying your phone number, and connecting to the API via a Business Solution Provider. This can take 3–7 days and requires a provider who handles the process.

Platforms like CodeWords manage the WhatsApp Business API setup entirely, including template approval, integration with your PMS (Dentally, Practice Web, Carestream), and ongoing message management. The technical complexity is abstracted away from the practice.

Patient demographics and channel preference

One practical consideration: patient demographics affect channel effectiveness. WhatsApp is nearly universal among UK adults under 60, with adoption above 80% in most age groups. Among adults over 65, adoption is lower — estimated at 55–65% in 2025.

For dental practices with a significant proportion of older patients, a mixed-channel approach may be appropriate: WhatsApp for patients who have opted in, SMS for those who haven't or who are less likely to be active WhatsApp users. Some PMS platforms allow channel preference to be recorded per patient.

The hybrid approach

Many practices that switch to WhatsApp for reminders do not abandon SMS entirely. A common configuration:

• Primary channel: WhatsApp for patients with a known WhatsApp number and opt-in consent
• Fallback channel: SMS for patients who have not opted in to WhatsApp or whose WhatsApp number is unknown
• Final fallback: Phone call from reception for patients who have not responded to either channel within 24 hours

This approach maximises coverage while directing the highest-engagement channel (WhatsApp) to the majority of patients.

Which channel should you use?

For most dental practices, the answer is WhatsApp as primary channel, with SMS as fallback. The response rate advantage is significant enough to justify the additional setup effort, and purpose-built platforms remove most of that friction.

If your practice management system already has a mature SMS integration and your no-show rate is below 5%, the incremental gain from switching to WhatsApp may not justify the changeover effort in the short term. If your no-show rate is above 8%, WhatsApp should be a priority.

Read more: how to reduce no-shows at your dental practice with WhatsApp reminders | best patient communication tools for dental clinics in 2026 | dental WhatsApp automation