Comparison Waterpik Cordless Plus WP-450 vs Panasonic EW-DJ40

The number of working nozzles that are standardly supplied with the device. Nowadays, options are quite common with both one and two or three nozzles in the kit; and in the most extensive sets, this number can be four or five or even more.

In many sets, several nozzles may have different purposes. For instance, an irrigator, in addition to its standard nozzle, might include orthodontic and periodontal nozzles. However, it's important to note that models with the same number of accessories in the kit can have different specific specializations. So, when making a choice, it's wise to consider not just the quantity but also the types of nozzles available. Additionally, there's an option where several identical interchangeable heads come with one handle. This configuration is particularly common in toothbrushes. It enables multiple individuals, such as family members, to use a single device, and such a set is usually more cost-effective than purchasing individual toothbrushes for each person.

Types of nozzles supplied as standard with the device.

The availability of nozzle types largely depends on the device's intended purpose (as discussed in the "Type" section). Toothbrushes typically offer standard round and oval-shaped nozzles, as well as options for sensitive teeth (also available in both round and oval shapes), and combined devices that may have multiple functions. In contrast, irrigators can come with various nozzles, including conventional ones, those designed for cleaning gum pockets (periodontal), and even nozzles for nasal irrigation. Devices intended for use with braces, implants and tongue cleaning are primarily found in irrigators, although they may also be compatible with some toothbrushes.

Here is a more detailed description of each of these options:

— Oval standard. Oval-shaped toothbrush heads are designed for standard cleaning intensity and are not specifically intended for sensitive teeth. The performance of these nozzles depends on the cleaning technology they employ (as explained below). For instance, models using reciprocating sweeping patt...erns offer more intensive treatment compared to similar round heads with reciprocating technology. However, this type of cleaning is less gentle and requires precision even for individuals with healthy teeth and gums. In the case of sonic and ultrasonic brushes, there is no significant difference, and oval-shaped heads are widely used because they cover a larger surface area, allowing for quicker toothbrushing. Occasionally, you may come across oval nozzles with a reciprocating-rotating mechanism, which, in terms of shape and application, are closer to round heads.

— Round standard. Round toothbrush heads are designed for standard cleaning and are not specifically intended for sensitive teeth. They are primarily used in models featuring reciprocating cleaning technology (as explained below). In comparison to their closest alternative, oval-shaped reciprocating-sweeping heads (as described earlier), round nozzles offer a gentler cleaning action and better access to hard-to-reach areas. They may not perform as well in cleaning open spaces, but this is typically not a critical issue. However, in "sonic" brushes, round heads are quite rare. In such cases, round heads do not offer significant advantages over oval ones, and their coverage area is noticeably smaller, which can reduce their overall effectiveness.

— Oval for sensitive teeth. A variation of the oval heads described above, optimized for the cleaning of sensitive teeth and gums (including inflammation in the oral cavity). Such devices are distinguished primarily by softer bristles than in standard nozzles; in addition, other design features may be provided to ensure the most delicate and gentle impact.

— Round for sensitive teeth. Round heads specially designed for sensitive teeth and gums. For round nozzles in general, see above; and the main difference of this variety is a softer bristle, which allows you to achieve the necessary accuracy and care during processing. In addition, the design may provide other solutions that eliminate discomfort when used with sensitive teeth or inflamed gums.

— Combined. A head that combines round and elongated (like an oval) sections. Allows you to combine the advantages of both options to some extent. Note that such heads are rarely used as regular ones, in most cases they are produced as interchangeable accessories.

— Standard for an irrigator. Classic irrigator heads designed mainly for cleaning healthy teeth and gums. The working part of such a head has the form of a nozzle of small diameter, and almost all modern irrigators and flossing systems are equipped with similar devices (see "Type"). Often, several standard heads are supplied in the kit at once — this allows several users to use one device at once without worrying about hygiene.

– Orthodontic (for braces). Specialized heads for removing plaque and dirt in hard-to-reach places under braces and other orthodontic structures. For this purpose, you can use a standard head, however, such devices more effectively cope with such tasks. Most often they come with irrigators and flossing systems, but they are also found in toothbrushes.

– Periodontal (cleaning pockets). Gum pocket cleaning heads are designed for cleaning the areas where the gums make contact with the teeth, known as "gingival pockets." These devices feature thin heads made from soft materials to provide gentle and precise cleaning. They are particularly effective for individuals with inflamed gums and certain other oral conditions, but they can also be beneficial for users with entirely healthy gums.

— For implants. Heads designed for cleaning implants, crowns, bridges, and similar dental structures serve a similar purpose as braces heads, focusing on effectively cleaning hard-to-reach areas. These heads may be included with toothbrushes, although they are more commonly found in the accessory sets of irrigators.

— Tongue cleaning. Special heads designed for cleaning the tongue and inner surface of the cheeks help maintain overall oral hygiene and combat bad breath by removing foreign plaque. In irrigators, these nozzles typically feature a spatula-like shape that scrapes away plaque, which is then washed away by a stream of water. Toothbrushes designed for tongue cleaning use a head with a specialized surface that replaces traditional bristles with low-height solid protrusions, typically less than a millimeter in height. These protrusions effectively clean the tongue, primarily focusing on this area.

— Nasal cleaning. An irrigator equipped with a head for nose washing serves multiple purposes, including the treatment of conditions like a runny nose or sinusitis, as well as general nasal hygiene and prevention. The head for this purpose includes a unique "plug" that securely seals one nostril to prevent liquid from flowing back. The nose washing procedure is typically performed with the head in a sideways position. Water or saline solution is gently introduced into one nostril, which is positioned higher, and flows out through the other nostril. The head is then turned to the opposite side, and the process is repeated. It's important to note that while this procedure is generally safe, there are specific contraindications, so consulting with an ear, nose, and throat (ENT) doctor before using an irrigator in this capacity is advisable.

Apart from the mentioned nozzles, modern toothbrushes and irrigators may come with various other types of attachments. Toothbrushes might include attachments for tartar removal, flossing heads with ultra-thin bristles that mimic dental floss, or specialized gum massage heads. Irrigators may offer specialized nozzles for intensive or gentle treatment, multi-jet nozzles and more.

Models of replacement heads supplied with the device.

This information is valuable for assessing the capabilities of a specific model and for sourcing additional, spare, or replacement nozzles, particularly for toothbrushes and dental centers that naturally use such devices (as indicated in "Type"). Firstly, it's advisable to replace the heads in these devices every 3-6 months, similar to regular toothbrushes. Secondly, if each user purchases their own nozzle while sharing a single handle, it's a cost-effective alternative to buying a separate brush for each individual, although it may be less convenient. Regardless, knowing the model of the interchangeable nozzle will save you time and effort when searching for compatible accessories.

The frequency of sound vibrations provided by a toothbrush with a sonic operating principle. This parameter also means the maximum pulsation frequency for toothbrushes with support for pulsating cleaning technology (see above) and for irrigators with a pulsed operating mode. For dental centers (see "Type"), data on the irrigator is usually specified here, and the pulsation frequency of the toothbrush (if this parameter is relevant for it) is indicated in a separate note

High frequency of movements and pulsations(from 40 thousand/min and higher) has a positive effect on the efficiency and quality of treatment, allowing you to quickly deal with dense plaque and even tartar. On the other hand, too intensive treatment can also be undesirable - for example, with high tooth sensitivity. All this is also relevant for irrigators - except that the operating frequencies in them are noticeably lower, such devices very rarely produce more than 2 thousand pulsations per minute. So when choosing, do not chase the maximum indicators of the frequency of movements and pulsations, but first of all it is important to take into account the individual characteristics of the user - for a full guarantee, it would not hurt to consult a dentist about this.

The pressure of the water supplied by the irrigator (see "Type") to the operating nozzle. Usually, this pressure can be adjusted within a certain range, since different situations and purposes require different processing intensity. The wider this range, the more versatile the device.

The lower limit of the pressure range in modern irrigators is around 30 kPa; similar values are set for procedures for sensitive teeth, for certain gum diseases and in other cases where the most gentle treatment is required. 400 – 500 kPa is considered an average level, and 600 – 650 kPa is considered high, such indicators allow for deep cleaning (see "Functions"). And higher values are rare, and they are used mainly when cleaning the tongue. However, it is best to consult with a dentist before purchasing an irrigator and choose a model for working pressure based on the recommendations received.

The volume of the reservoir for water (or treatment solution) provided in the design of the irrigator or flossing system (see "Type").

In general, the larger the tank, the less often you have to refill the device, but the larger, heavier and more expensive the whole structure is. Thus, in portable format irrigators, where the water tank is built right into the handle, the capacity is small — even in the largest models it usually does not exceed 400 ml, a larger tank would noticeably complicate use. However, even the smallest volumes in such cases are usually enough for at least one standard procedure. But stationary models, consisting of a handle and a separate main unit, can hold very significant volumes of water — up to 1.5 L or even more.

Additional items supplied with the device (in addition to the base and attachment set).

The most popular types of such items nowadays are charging stand, accessory stand, UV sanitizer and case ; Here is a more detailed description of each option:

— Charging stand. A battery charging device designed as a stand serves the dual purpose of recharging the battery and offering added convenience for storing the device. It's worth noting that this function can apply to dental centers, even if they primarily operate on mains power (as indicated in the "Type of power" section). In such cases, the toothbrush included with the dental center typically runs on batteries, and the charging stand is typically integrated directly into the main unit of the dental center for ease of use.

— Stand for accessories. A device designed to hold various accessories, primarily interchangeable nozzles, can come in different designs. For example, in toothbrushes and portable irrigators, this device is often integrated into a charging stand, which includes both a charging socket and open compartments for accessories. In irrigators and fixed-layout dental centers, these compartments are usually built into the main unit or the lid of the water tank. In this case, the compartments are typically covered with lids for hygiene reasons, making it...a more hygienic option. Regardless of the design, having a dedicated stand for accessories enhances the convenience of storing them.

— UV sanitizer. A device that uses ultraviolet (UV) radiation for disinfecting the device, particularly replaceable nozzles, is typically designed as a distinctive container. In some models, this container also serves as a cover or case. The disinfection process effectively eliminates the majority of pathogenic bacteria and viruses, all without the need for additional chemicals and ensuring safety as the radiation remains confined within the container. However, it's important to note that UV disinfection is not effective against regular dirt and debris, so having this function doesn't eliminate the need to clean the nozzle through washing.

— Case / cover. The device comes with a storage and carrying container, which can be either a hard case or a soft cover. Hard cases offer better protection, while soft covers are more compact and can be rolled up when not in use. Regardless, both of these accessories are highly convenient for storage and transportation. They safeguard the contents from dirt and damage, and in many cases, provide space to store additional accessories, reducing the risk of losing them. While you could use makeshift packaging for the same purpose, the provided container is typically more practical.

This refers to the maximum duration a device can run continuously when powered by a fully charged battery or fresh batteries. It's worth noting that this metric may also apply to models designed for mains power, such as flossing systems that include rechargeable toothbrushes, in which case we're referring to the battery life of these toothbrushes.

It's important to note that device specifications typically indicate the maximum runtime under ideal conditions, often in the most energy-efficient mode of operation (and for models with replaceable batteries, using high-quality batteries). The actual battery life can vary depending on specific usage conditions. However, this parameter still serves as a valuable basis for comparing different models. Generally, differences in the claimed operating time correspond proportionally to the real differences in battery life. For example, if one toothbrush has a stated operating time of 20 minutes and another boasts 40 minutes, in practice, their battery life (under similar conditions) will likely differ by approximately two times.

It's important to consider that, for toothbrushes, this parameter can help estimate the number of brushing sessions you can expect on a single charge. Typically, the recommended daily brushing duration is 2 minutes. So, if a toothbrush has an operating time of 30 minutes, it's sufficient for approximately 15 cleaning sessions (or more realistically, around 14 or 13).

The time required to charge the battery from zero to 100% in a device with the appropriate power type (see above). This parameter can vary from 1 – 3 hours in relatively simple and low-power devices to a day in advanced models with capacious batteries. At the same time, the longer the maximum operating time on a charge (see above), the longer, usually, the time required for charging, although there is no hard dependence here.

In general, having fast charging capabilities improves the convenience of a device by reducing interruptions in its operation. However, there is a trade-off to consider: fast charging often means either a smaller battery capacity or a higher price due to the use of specialized technologies to speed up the charging process. When evaluating this parameter, it's essential to think about how you intend to use the device. For instance, if a toothbrush or irrigator is solely used at home by one person and comes with a charging stand, fast charging may not be a critical factor. The device remains consistently charged as it's constantly on the charger, and its battery doesn't deplete significantly during one use. The time between sessions, usually around 8 to 12 hours, is more than enough to maintain a charged battery, even for devices with slower charging. However, if you plan to use the device while traveling, where access to power outlets is sporadic, it's preferable to have minima...l charging time to ensure you can recharge quickly during your trips.