Karim Elhennawy

Global burden of molar incisor hypomineralization

OBJECTIVES We aimed to systematically review and meta-analyze the global, super-regional, regional and national prevalence of molar-incisor-hypomineralization (MIH) and to determine the numbers of prevalent and incident cases on different spatial scales. The review was registered (PROSPERO CRD42017063842). SOURCES Five electronic databases (Medline, EMBASE, LILACS, Web of Science, Google Scholar) were searched systematically. STUDY SELECTION Observational studies on the prevalence of MIH were included and the prevalence on different spatial scales (global, super-regional, regional, national) synthesized using random-effects meta-analyses. The prevalence was then regressed on a large set of methodological, socioeconomic and environmental variables to estimate the global burden (incident and prevalent cases) of MIH. DATA Of 2239 identified studies, 99 studies on 113,144 participants from 43 countries were included. The meta-analysis yielded a mean (95% CI) prevalence of 13.1% (11.8-14.5%), with significant differences between super-regions, regions and countries. The number of prevalent cases in 2015 was estimated at 878 (791-971) million people, while the number of incident cases in 2016 was 17.5 (15.8-19.4) million. Of these, 27.4% (23.5-31.7%) (in mean, 240 million prevalent and 4.8 million incident cases, respectively) were or will be in need of therapy due to pain, hypersensitivity or posteruptive breakdown. Heavily populated countries contribute significantly to the burden of prevalent cases, while growing countries like India, but also Pakistan or Indonesia rank first with respect to the number of incident cases. CONCLUSIONS MIH is highly prevalent across the globe. Certain (mainly low- and middle income) countries shoulder the majority of this burden. Clinical significance The consistently high prevalence and the large proportion of cases in need of care should be considered by both clinicians in their daily practice and healthcare planners and policy makers.

Industry sponsorship in trials on fluoride varnish or gels for caries prevention

OBJECTIVES Fluoride is effective for caries prevention, but trials on fluoride varnish or gels are often industry-sponsored. We assessed trial design and findings in sponsored and nonsponsored trials on fluoride varnish and fluoride gels for caries prevention. METHODS Data on trials included in the most recent Cochrane Reviews on fluoride varnish and fluoride gels were extracted. Sample sizes/age/dentition, year/country of publication, follow-up, test and control, risk of bias and spin (claims of a beneficial effect that were not supported by reported data) were assessed. Studies were categorized as certainly, possibly and not sponsored, and statistically compared. Inverse-generic meta-analysis and multivariable weighted least-squares meta-regression were used to assess impact of sponsorship status on effect estimates. RESULTS Based on 19 nonsponsored, 14 possibly sponsored and 11 certainly sponsored trials, sponsored studies were published significantly earlier, always had >1 test group, and had significantly lower risk of spin. Caries-preventive effects were higher in earlier trials, without indication for sponsorship bias in trials published until 1990 (there were no sponsored trials afterwards). If assessing the overall body of evidence and accounting for confounders, the caries-preventive effect was significantly associated with year of publication (β: -0.06, 95% CI: -0.10/-0.02), but not sponsorship status. CONCLUSIONS Industry-sponsorship bias had limited impact on the overall evidence.

Managing molars with severe molar-incisor hypomineralization: A cost-effectiveness analysis within German healthcare

OBJECTIVES Dentists have a range of options for managing molars with severe molar-incisor hypomineralization (MIH), each with different long-term implications. The cost-effectiveness of managing molars with severe MIH was assessed. METHODS A mixed public-private-payer perspective within German healthcare was adopted. Individuals with one to four severely MIH-affected molars were followed over their lifetime. We compared: (1) removal of the tooth/teeth and orthodontic alignment of the second and third molars (Ex/Ortho); (2) restoration of the tooth using resin composite (Comp); (3) restoration using an indirect metal crown after temporizing it using a preformed metal crown (PMC/IR). The health outcome was tooth retention years. Transition probabilities were estimated based on the best available evidence. Cost calculations were based on German dental fee catalogues. Monte-Carlo microsimulations were performed for cost-effectiveness-analysis. RESULTS If extraction was performed at the optimal age (9.5/11 years for maxillary/mandibular molars), Ex/Ortho was most cost-effective (67 years, 446-938 Euro). Comp (51 years, 1911 Euro) and PMC/IR were dominated (50 years, 2033 Euro). This cost-effectiveness ratio was also determined when >1 molar was treated. If extraction was performed later, assuming no spontaneous alignment, Ex/Ortho was more costly than Comp, at least when only 1 molar was treated. CONCLUSIONS For molars with severe MIH, extraction at the optimal age and, if needed, orthodontic alignment can be cost-effective, especially when >1 molar is affected. For single molars where the chance of spontaneous alignment is low, Comp might also be considered. These findings apply to German healthcare and within the limitations of this study only. CLINICAL SIGNIFICANCE When deciding how to manage molars with severe MIH, both tooth retention, with lower costs but higher needs for re-treatments, and tooth removal, with possible need for orthodontic alignment, can be considered. Considering cost-effectiveness, the latter may be preferable, especially if the age of extraction is chosen correctly, or several molars are affected.

In vitro performance of the DIAGNOcam for detecting proximal carious lesions adjacent to composite restorations

OBJECTIVES To assess the accuracy of near-infrared-light transillumination (DIAGNO) compared to visual-tactile (VT) and radiographic (RA) evaluation of proximal carious lesions adjacent to composite restorations in vitro. METHODS Two hundred extracted posterior permanent human teeth with occluso-proximal composite restorations were allocated to 50 groups of four posterior teeth, and mounted in a pilot-tested diagnostic model in a dummy head. The teeth were independently assessed by two examiners. Transverse microradiography and visual assessment served as reference tests to detect any lesions (prevalence 24%) and cavitated lesions (18%), respectively, adjacent to restorations. Sensitivity, specificity, positive and negative predictive values and the area under the receiver-operating-characteristics curve (AUC) were calculated. RESULTS To detect any proximal carious lesions adjacent to composite, the mean sensitivity/specificity were 0.63/0.95 for DIAGNO, 0.70/0.88 for RA when lesions radiographically extending into enamel and dentin were considered, 0.26/0.98 for RA when only lesions extending into dentin were considered, and 0.31/0.96 for VT. For cavitated lesions adjacent to proximal composite restorations, these values were RA (enamel and dentin) 0.84/0.88, RA (dentin) 0.34/0.99, DIAGNO 0.69/0.94 and VT 0.40/0.97. AUC did not differ significantly between RA and DIAGNO, while VT showed significantly lower values (p < 0.05). CONCLUSION Within the limitations of this study, DIAGNO seems useful for detecting proximal carious lesions adjacent to restorations. CLINICAL RELEVANCE Near-infrared-light transillumination could be used as a radiation-free adjunct or alternative to RA for detecting carious lesions adjacent to composite restorations.

Effects of calcium silicate cements on dental pulp cells: A systematic review

OBJECTIVES The aim of this study was to evaluate the biocompatibility, odontogenic, angiogenic and inflammatory effects of commercially available calcium silicate cements (CSCs) on dental pulp cells. DATA In vitro, animal and human in vivo studies reporting on biocompatibility, odontogenic, angiogenic and inflammatory effects of CSCs on dental pulp cells were screened using a systematic review, and a descriptive analysis performed. SOURCES We searched Medline via PubMed, Google Scholar and Scopus, followed by hand search and cross-referencing. STUDY SELECTION From 7007 identified studies; 38 were included. At least one MTA-type product was evaluated in each study, with ProRooT MTA being the most frequently assessed, followed by Biodentine and iRoot BP Plus. Nearly all CSCs exhibited a high biocompatibility and induced odontogenic and angiogenic effects. There was great heterogeneity in methodology and findings. In vivo, effects differed between materials; also, differences between human or animal pulp cell effects were noted. In vitro, the dilution of the cement, the period of exposure to the CSC and the specific effect measure influenced the outcomes. No CSC was clearly superior to alternatives. CONCLUSIONS All commercially available CSCs are biocompatible, exhibit comparable and favorable effects on odontogenic differentiation of dental pulp cells in vitro and can efficiently enhance dentin bridge formation of high quality with minimal inflammation. No specific CSC can be recommended. CLINICAL SIGNIFICANCE Most CSCs are highly biocompatible, promoting pulp healing at minimal pulp inflammation. While the variation in methodology limits comparisons across studies, it seems that nearly all CSCs show favorable effects on dental pulp cell. We are unable to recommend one specific material over the others.

Oral manifestations, dental management, and a rare homozygous mutation of the PRDM12 gene in a boy with hereditary sensory and autonomic neuropathy type VIII: a case report and review of the literature

BackgroundHereditary sensory and autonomic neuropathy type VIII is a rare autosomal recessive inherited disorder. Chen et al. recently identified the causative gene and characterized biallelic mutations in the PR domain-containing protein 12 gene, which plays a role in the development of pain-sensing nerve cells. Our patient’s family was included in Chen and colleagues’ study. We performed a literature review of the PubMed library (January 1985 to December 2016) on hereditary sensory and autonomic neuropathy type I to VIII genetic disorders and their orofacial manifestations. This case report is the first to describe the oral manifestations, and their treatment, of the recently discovered hereditary sensory and autonomic neuropathy type VIII in the medical and dental literature.Case presentationWe report on the oral manifestations and dental management of an 8-month-old white boy with hereditary sensory and autonomic neuropathy-VIII over a period of 16 years. Our patient was homozygous for a mutation of PR domain-containing protein 12 gene and was characterized by insensitivity to pain and thermal stimuli, self-mutilation behavior, reduced sweat and tear production, absence of corneal reflexes, and multiple skin and bone infections. Oral manifestations included premature loss of teeth, associated with dental traumata and self-mutilation, severe soft tissue injuries, dental caries and submucosal abscesses, hypomineralization of primary teeth, and mandibular osteomyelitis.ConclusionsThe lack of scientific knowledge on hereditary sensory and autonomic neuropathy due to the rarity of the disease often results in a delay in diagnosis, which is of substantial importance for the prevention of many complications and symptoms. Interdisciplinary work of specialized medical and dental teams and development of a standardized treatment protocols are essential for the management of the disease. There are many knowledge gaps concerning the management of patients with hereditary sensory and autonomic neuropathy-VIII, therefore more research on an international basis is needed.

Structural, mechanical and chemical evaluation of molar-incisor hypomineralization-affected enamel: A systematic review

OBJECTIVES To systematically assess and contrast reported differences in microstructure, mineral density, mechanical and chemical properties between molar-incisor-hypomineralization-affected (MIH) enamel and unaffected enamel. METHODS Studies on extracted human teeth, clinically diagnosed with MIH, reporting on the microstructure, mechanical properties or the chemical composition and comparing them to unaffected enamel were reviewed. Electronic databases (PubMed, Embase and Google Scholar) were screened; hand searches and cross-referencing were also performed. RESULTS Twenty-two studies were included. Fifteen studies on a total of 201 teeth investigated the structural properties, including ten (141 teeth) on microstructure and seven (60 teeth) on mineral density; six (29 teeth) investigated the mechanical properties and eleven (87 teeth) investigated the chemical properties of MIH-affected enamel and compared them to unaffected enamel. Studies unambiguously found a reduction in mineral quantity and quality (reduced Ca and P content), reduction of hardness and modulus of elasticity (also in the clinically sound-appearing enamel bordering the MIH-lesion), an increase in porosity, carbon/carbonate concentrations and protein content compared to unaffected enamel. FINDINGS were ambiguous with regard to the extent of the lesion through the enamel to the enamel-dentin junction, the Ca/P ratio and the association between clinical appearance and defect severity. CONCLUSIONS There is an understanding of the changes related to MIH-affected enamel. The association of these changes with the clinical appearance and resulting implications for clinical management are unclear. CLINICAL SIGNIFICANCE MIH-affected enamel is greatly different from unaffected enamel. This has implications for management strategies. The possibility of correlating the clinical appearance of MIH-affected enamel with the severity of enamel changes and deducing clinical concepts (risk stratification etc.) is limited.