Influence of Bariatric Surgery on Salivary Flow: a Systematic Review and Meta-Analysis

Dental outcomes after gastric bypass and sleeve gastrectomy: a register-based study

BACKGROUND

Bariatric surgery has been shown to cause a negative impact on oral health, as reflected by postsurgical increase of caries-related dental interventions.

OBJECTIVES

The aim of this study was to compare dental intervention rates after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG).

SETTING

Nationwide and register-based (Sweden).

METHODS

This 2-staged matched cohort study included all adults who underwent RYGB (n = 26,594) or SG (n = 3416) between 2011 and 2015, registered in the Scandinavian Obesity Surgery Register. Propensity score matching was used to match SG patients to RYGB patients, based on several covariates. The follow-up time was 3 years after surgery. The dental variables were collected from the Dental Health Register, including tooth extractions, restorative interventions (dental fillings), and endodontic interventions (root canal treatment).

RESULTS

In total, 3317 RYGB and 3317 SG patients were included. Both groups showed increased dental event rates postoperatively. RYGB patients had significantly higher event rates compared with SG postoperatively regarding all interventions, restorative and endodontic interventions.

CONCLUSIONS

The negative effect on dental outcomes in terms of dental fillings and tooth extractions were higher after RYGB than after SG. The reasons are not clear. More research is needed to replicate these findings, to understand the mechanisms, and further delineate the significance of the surgical method.

Oral Health in Individuals After Bariatric Surgery: A Systematic Scoping Review

This scoping review appraises the available literature that investigates oral health after bariatric surgery (BS). Forty-two records were included (33 original studies and 9 systematic reviews). Bariatric surgery had a negative impact on the oral health related quality of life (three out of six studies). Relatively few studies found improvement following BS, probing pocket depth (2/10), clinical attachment level (1/9), bleeding on probing (3/10) and plaque (3/8). Conversely, BS was negatively associated with the DMFT (4/6), tooth wear (4/6) and oral radiographic findings (1/1). There was conflicting evidence regarding salivary parameters. To conclude, the literature on oral health in bariatric surgery patients is continuously growing. Positive as well as negative associations between oral health parameters and bariatric surgery are observed.

EFFECT OF AN ORAL HEALTH PROMOTION PROGRAM ON GASTROPLASTY PATIENTS: A RANDOMIZED CLINICAL TRIAL

BACKGROUND

Bariatric surgery can cause oral health problems in individuals, such as an increase in dental caries, periodontal diseases and dental erosion, which can be avoided if oral health promotion actions are implemented.

AIMS

To assess the impact of an oral health promotion program implemented among gastroplasty patients.

METHODS

This randomized clinical trial involved 208 patients undergoing gastroplasty; they were divided into two groups: Intervention Group, with participation in the Oral Health Promotion Program for Bariatric Patients, or Control Group. Assessments were carried out preoperatively, and six and 12 months postoperatively. The oral conditions assessed were: dental caries, periodontal diseases, tooth wear, dental plaque, and salivary flow. Sociodemographic information was obtained through application of structured questionnaires. For data analysis, the Chi-Square, Fisher's Exact, and Mann-Whitney tests were performed - α=5%.

RESULTS

Patients in the Intervention Group, when compared to those in the Control Group, presented: fewer changes in enamel (6M: p<0.0001; 12M: p=0.001), in dentin (6M: p<0.0001; 12M: p<0.0001), moderate tooth wear (6M=0.002; 12M=0.005), gingival bleeding (6M: p<0.0001), dental calculus (6M=0.002; 12M: p=0.03), periodontal pocket 4-5 mm (6M=0.001; 12M: p=<0.0001); greater reduction in the bacterial plaque index (6M: p<0.0001; 12M: p<0.0001), and increased salivary flow (6M: p=0.019).

CONCLUSIONS

The oral health promotion program had a positive impact on the prevention and control of the main problems to the oral health of the gastroplasty patients.

Effect of sleeve gastrectomy on the levels of oral volatile sulfur compounds and halitosis-related bacteria

Background

The association between sleeve gastrectomy and halitosis remains relatively unknown. Therefore, this study aimed to evaluate the effect of sleeve gastrectomy on halitosis and the oral bacterial species associated with halitosis in patients with obesity.

Methods

This was a prospective longitudinal cohort study that examined patients before and after sleeve gastrectomy and followed the patients at three time intervals (1, 3, and 6 months) after sleeve gastrectomy. Clinical periodontal measurements (plaque index [PI], gingival index [GI], and probing depth [PD]) were obtained. In addition, plaque samples were collected for quantification of the periodontopathogenic bacteria: Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Fusobacterium nucleatum using real-time quantitative polymerase chain reaction (qPCR). In addition, breath samples were collected to analyze the concentration of volatile sulfur compounds (VSCs), namely hydrogen sulfide (H2S), methyl mercaptan (CH3SH), and dimethyl sulfide (CH3SCH3), via portable gas chromatography (Oral Chroma™).

Results

Of the 43 patients initially included, 39 completed the study, with a mean age of 32.2 ± 10.4 years. For PI and GI repeated measurements one way analysis of variance showed a significant increase (p-value < 0.001 for both) one month after surgery, with mean values of 1.3 and 1.59, respectively, compared to the baseline. During the same period, the number of P. gingivalis increased, with a p-value = 0.04. Similarly, the levels of hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) increased significantly in the first month after surgery (p-value = 0.02 and 0.01, respectively).

Conclusion

This study demonstrated that sleeve gastrectomy may lead to increased halitosis one month post-surgery, attributed to elevated and P. gingivalis counts, contributing to the development of gingivitis in obese patients who underwent sleeve gastrectomy. This emphasizes the importance of including oral health professionals in the multidisciplinary team for the management of patients undergoing bariatric surgery.

Metabolic surgery and oral health: A register-based study

OBJECTIVE

The impact of weight loss surgery on oral health is not clear. The aim of the present study was to investigate its impact on the risk for dental interventions.

MATERIALS AND METHODS

All adults who underwent metabolic surgery in Sweden between January 1, 2009 and December 31, 2018 were identified in the Scandinavian Obesity Surgery Registry (SOReg; n = 53,643). A control cohort from the general population was created, matched 10:1 on sex, age and place of residence (n = 536,430). All individuals were followed in the Swedish Dental Register regarding event rates for four types of dental intervention: restorative, endodontic and periodontal interventions, and tooth extractions.

RESULTS

The surgical cohort had increased interventional rates postoperatively regarding all studied outcomes except periodontal interventions. Dental interventions were more common in the surgical cohort both pre- and postoperatively. The difference between the groups increased markedly in the postoperative period. The between-group comparison postoperatively showed increased event rates for restorations (IRR 1.8; 95% CI 1.7-1.8), extractions (1.9; 95% CI 1.9-2.0) and endodontics (2.1; 95% CI 2.0-2.1).

CONCLUSION

The surgical intervention might cause a substantial negative impact on oral health. These results imply an important role for counselling metabolic surgery patients regarding preventive oral health measures.

Associations between Zinc Deficiency, Taste Changes, and Salivary Flow Rates following Gastric Bypass and Sleeve Gastrectomy Surgeries

BACKGROUND

The prevalence of taste change (hypogeusia) and its association with zinc deficiency is unclear due to differences in methods of assessment. We investigate the prevalence of hypogeusia using mixed methods and link it with changes in zinc levels following mini gastric bypass (MGB) and sleeve gastrectomy (SG).

METHODS

This was a prospective observational study of MGB (N = 18) and SG (N = 25). Hypogeusia was evaluated by using a validated questionnaire and by taste strips procedure along with serum zinc levels and salivary flow rate measurements.

RESULTS

The mean age was 40.0 ± 9.7 years; 60.5% were female. By using a questionnaire, MGB patients experienced greater hypogeusia than SG at 3 months (72.0% vs 36.0%; (p=0.03)), but not at 6 months (56.0% vs 45.0%; (p=0.74)), respectively. Using taste strips, at 6 months, more MGB patients experienced hypogeusia compared with SG (44.0% vs 11.0%; p=0.03). Zinc level was reduced following MGB at 6 months (85.6 ± 16.9 μgm/dl vs 67.5 ± 9.2 μgm/dl; (P=0.004)) but was increased at 6 months following SG (76.9 ± 11.4 vs 84.9 ± 21.7 μgm/dl). Reduction in the rate of salivary flow was observed in 66.0% and 72.0% of MGB and SG patients, respectively, at 3 months and in 53.0% and 70.0% at 6 months.

CONCLUSION

Taste change is more prevalent following MGB compared with SG, especially at 6 months postoperation which parallel with changes in zinc levels. More than half of all patients who had undergone bariatric surgery (BS) had low to very low salivary flow rates during the follow-up. This study suggests an association between low zinc levels and reduced salivary flow with hypogeusia following BS.

Mechanisms of Action of Bariatric Surgery on Body Weight Regulation

Bariatric surgery is an effective treatment modality for obesity and obesity-associated complications. Weight loss after bariatric surgery was initially attributed to anatomic restriction or reduced energy absorption, but now it is understood that surgery treats obesity by influencing the subcortical areas of the brain to lower adipose tissue mass. There are three major phases of this process: initially the weight loss phase, followed by a phase where weight loss is maintained, and in a subset of patients a phase where weight is regained. These phases are characterized by altered appetitive behavior together with changes in energy expenditure. The mechanisms associated with the rearrangement of the gastrointestinal tract include central appetite control, release of gut peptides, change in microbiota and bile acids. However, the exact combination and timing of signals remain largely unknown.

Impact of bariatric surgery on oral health: a systematic review and meta-analysis

OBJECTIVE

To evaluate the impact of bariatric surgery (BS) on the oral health status of obese individuals.

MATERIAL AND METHODS

The search was performed on the Cochrane Library, Embase, Latin American and Caribbean Literature on Health Sciences (LILACS), LIVIVO, PubMed/Medline, Scopus, and Web of Science databases. Grey literature was also consulted through Google Scholar, OpenGrey, ProQuest, and MedRxiv. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal tool. Pre- and post-surgical moments were compared through random effects meta-analysis. The GRADE (Grading of Recommendations, Assessment, Development and Evaluations) assessment tool was used to judge the certainty of evidence.

RESULTS

After searching the databases, 908 references were retrieved, with 30 articles selected for synthesis. When comparing the pre- and postoperative moments, there was no difference in the index of decayed, missing, or filled teeth. Furthermore, salivary flow and probing depth presented a slight increase. Post-surgery patients showed an increase (%) in tooth wear at the dentin level [MD = -6.23; IC95% = -8.45--4.01; I² = 0%].

CONCLUSION

Patients undergoing BS show no difference when considering the rate of caries or missing teeth and little to no effect was observed on salivary flow rates and periodontal probing depth. On the other hand, greater attention should be given to dentin wear in post-surgical patients of BS.

CLINICAL RELEVANCE

Patients undergoing BS should receive careful monitoring regarding oral health by doctors, dentists, and the entire multidisciplinary team involved before and after the surgical procedure.

Mechanisms of Weight Loss After Obesity Surgery

Obesity surgery remains the most effective treatment for obesity and its complications. Weight loss was initially attributed to decreased energy absorption from the gut but has since been linked to reduced appetitive behavior and potentially increased energy expenditure. Implicated mechanisms associating rearrangement of the gastrointestinal tract with these metabolic outcomes include central appetite control, release of gut peptides, change in microbiota, and bile acids. However, the exact combination and timing of signals remain largely unknown. In this review, we survey recent research investigating these mechanisms, and seek to provide insights on unanswered questions over how weight loss is achieved following bariatric surgery which may eventually lead to safer, nonsurgical weight-loss interventions or combinations of medications with surgery.

Oral health profile of postbariatric surgery individuals: A case series

Objectives

To describe the oral health profile of individuals who had undergone gastric bypass surgery (GBP) or sleeve gastrectomy (SG) to generate hypotheses for further studies.

Material and Methods

Fourteen individuals treated with GBP or SG surgery ≥ 2 years ago and with observed and/or perceived oral problems were recruited to a case series. The documentation included clinical and radiographic examinations, biomedical sampling, and self‐reported diet and questionnaires. The results are presented descriptively.

Results: The age range was 31 to 66 years and all had a BMI > 25 (range 25.4–44.7). Only four participants were fully dentate. Eleven out of 14 individuals exhibited severe decay. A majority had poor oral hygiene and high bacterial counts. The flow rates of unstimulated saliva were extremely low and hyposalivation was present in ten of the fourteen cases. Most perceived several oral health problems, such as chewing difficulty and tooth hypersensitivity.

Conclusions

Individuals who had undergone GBP or SG surgery had poor clinically diagnosed oral health and perceived oral health problems. Longitudinal studies are needed to monitor the patients' oral health, from before bariatric surgery to long‐term postoperatively.