The main objective of this study was to highlight the impact of dental implant treatment on the OHRQoL of a group of patients. The data collected showed that OHRQoL was improved after implant treatment, regardless of the GOHAI fields measured.
The evaluation tool used most commonly in many studies conducted on the OHRQoL of patients is the OHIP (Oral Health Impact Profile) [1, 24, 25]. However, the OHIP has not been validated in French and therefore could not be used for this study. For similar reasons, the Visual Analogue Scales (VAS) used in many studies to assess the OHRQoL of patients could not be used in the present study. However, a validated French version of the GOHAI was available . The GOHAI simply consists in a series of clear and concise questions grouped in twelve items which allow accurate analysis of the functional and psychosocial domains and of discomfort and pain. This questionnaire is reproducible, easy to use and has already been applied previously in the evaluation of the impact of oral treatment [26, 27]. After taking into account all these considerations, the GOHAI was used for this study. The methodology used in the present study is similar to that of previous studies [26–28], though it presents some biases and weaknesses. First, the lack of investigator calibration could be a limitation. Furthermore, the patients included in this study originated from a single dental practice and it is not possible to determine whether the results are practitioner-dependent. Furthermore, the long-term impact of implant treatment on the OHRQoL could not be measured due to the fact that patient follow-up did not exceed 2 years. Similarly, only the type of edentulousness was considered but not the different surgical procedures that were performed (Immediate loading, post-extractional, etc.). Additional studies should be conducted to improve these points.
Before treatment, the results also displayed great variability in the GOHAI scores according to the type of edentulousness: the greater the need for treatment, the lower the GOHAI scores. This variability was present within every type of edentulousness, in particular with participants scheduled for complete treatment. Therefore, the OHRQoL of the patients was very variable. These results confirm a previously published study . Three months after implant treatment, the GOHAI-Add score for all the patients increased and displayed less variation, regardless of the type of treatment. The GOHAI mean score reached 54 while the change in the GOHAI score was greatest for the patients with the fewest teeth.
Implant treatment led to an improvement of OHRQoL in the three fields of the GOHAI (functional, psychosocial, discomfort and pain). Before treatment, the functional GOHAI score was lower for those with the fewest teeth but, afterwards, scores varied less and were no longer significantly different. Indeed, participants presented the same masticatory and phonetic abilities, regardless of the type of treatment performed. As with previous studies, these results confirmed the physiological and functional benefits of implant treatment [26, 29, 30]. With respect to the psychosocial field, the GOHAI scores before treatment were significantly lower for those with fewer teeth (P < 0.001). After treatment, these scores were no longer statistically different according to the type of prosthetic treatment (P < 0,001). A low GOHAI score in the psychosocial field reflects a difficulty for maintaining regular social relationships, embarrassment at eating in front of other people, concerns over dental, and/or gingival status, or over dentures. In particular, the treatment greatly improves the everyday life of complete denture wearers [27, 31, 32]. Initially, exploration of the “discomfort and pain” field did not reveal any significant difference between the different types of edentulousness. A significant improvement of these scores was observed after treatment. This field studied comfort during meals, consumption of analgesics and sensitivity of teeth or gums to warmth, and cold and sweet food. The scores before treatment were low and confirmed the need for care for all of the participants included in the study.
This study emphasized the fact that the OHRQoL of people who underwent single implant treatment was improved. These results agree with those of a previous study  in which 90% of the patients evaluated with a VAS were satisfied by implant treatment when considering the aesthetic and functional points of view. With regards to partial treatment by implants, a significant improvement of OHRQoL was observed, thus corroborating results obtained in another study that measured OHRQoL using the OHIP. Similarly, the OHRQoL of the partially dentate participants was lower than that of fully dentate participants . The present work also showed a significant improvement of OHRQoL in retained or fixed complete denture wearers, as previously reported in another study, which used the OHIP and OIDP as evaluation tools . In addition, two studies using the OHIP did not demonstrate any difference in OHRQoL between conventional and implant-retained complete denture wearers [35, 36]. On the other hand, before treatment, participants that accepted implant treatment presented an initially poorer OHRQoL than that of conventional full removable denture wearers. Subsequently, the improvement of their OHRQoL was also greater. Two metanalyses calculated comparable results [30, 37]. It is possible that the sole fact of receiving an implant treatment has a positive and subjective impact on individuals. For a number of patients, this “modern” technique is the best way to improve their oral state and thus to improve their OHRQoL. Moreover, it has also been shown that treatment with conventional or implant-retained dentures has an impact on social and sexual activities. Two months after treatment, participants wearing full dental implants showed higher OHIP scores, especially in the following activities; eating, speaking, kissing, and yawning .
The GOHAI scores after treatment were similar for individuals who underwent fixed or removable complete treatment. This was already demonstrated in previous studies using OHIP as a tool [32, 39]. Finally, all the patients were satisfied about their chewing ability and the aesthetics. Maintaining oral hygiene was easier for the wearers of removable prostheses on implants. However, regarding the psychosocial aspect, participants wearing a fixed prosthesis were generally more satisfied than others, as previously described by Brennan and co-workers (2010) . More often, the improvement of OHRQoL would be better with a fixed prosthesis . However, a study using VAS showed improved oral quality of life for removable treatments on implants .