Ultrasonic scalers have been shown effective in removing subgingival calculus. However, it may cause alteration to the tooth surface as well as discomfort to patients. Advances in scaler tip designs may reduce these effects. Limited studies have investigated the influence of scaler tip designs on tooth surface and patients' comfort. This study aimed to evaluate the influence of scaler tip designs on patients' pain perception.

Scaling is a common procedure performed by general dental practitioners and dental specialists. Unfortunately, scaling has been associated with unpleasant dental treatment and to some extent, a painful experience (Berggren & Meynert, 1984). Studies also have demonstrated that scaling using ultrasonic scalers can cause tooth surface roughness and tooth substance loss (Jepsen et al., 2004; Kawashima et al., 2007). Rough tooth surface will increase retention of plaque and has been shown associated with early biofilm formation (Teughels et al., 2006). Subsequently, this would increase the risk for development and progression of periodontal disease. Whereas, tooth substance loss may lead to exposed dentinal tubules, and subsequently root sensitivity. Root sensitivity was reported to affect half of patients receiving periodontal therapy (Von Troil et al., 2002). This led to discomfort among patients and avoidance to dental treatment in future.

Advanced development in scaler tip designs has provided opportunities to deliver scaling treatment that is less aggressive to tooth surfaces and most importantly, to reduce the discomfort to patients. The design of the scaler tip has influenced the performance of ultrasonic scalers characterised by the displacement amplitude (Lea et al., 2003b). Displacement amplitude is the lateral movement of scaler tip that is thought to contribute to the aggressiveness of scaling procedure. Several studies have investigated the factors that may influence displacement amplitude, such as power setting and type of generator (Lea et al., 2003a), tip wear (Lea et al., 2006) and scaler tip designs (Lea et al., 2003a). However, to date, there were limited studies that investigated the effect of ultrasonic scaler tip design particularly slim and wide scaler tip on tooth surface roughness, tooth substance loss, and patients' pain perception.

In a clinical setting, if there were two treatment methods that provide similar levels of effectiveness but different levels of discomfort and damage to tooth surface patient will opt for the more comfortable and conservative method. Therefore, this study investigated the influence of scaler tip designs on tpatients' pain perception following scaling.

Inclusion Criteria:

• Healthy patients aged 20-40 years who had anterior maxillary teeth from teeth #13 to #23.
• Diagnosed with chronic gingivitis and/or mild chronic periodontitis and presented with bleeding on probing (BOP) and minimal calculus from teeth #13 to #23

Exclusion Criteria:

• Smokers,
• Patients who had dentinal hypersensitivity, crowns, large restorations, non-vital teeth, acute dental infections or cervical lesions involving teeth #13 to #23.
• Patients who were on long-term non-steroidal anti-inflammatory drug therapy, undergoing orthodontic treatment or using removable partial dentures involving teeth from teeth #13 to #23

Single blinded (subject)