Antibiotic therapy as an adjunct to scaling and root planing in smokers


It has long been established that smoking is a significant modifying factor in the progression of periodontal disease and eventual tooth loss (Dietrich et al. 2015; Zeng et al. 2014). The established treatment of periodontal disease is based on the elimination of pathogens through subgingival scaling and root planing (SRP), if periodontal disease remains following this initial ‘hygienic phase’ then treatment can be repeated with the addition of systemic antibiotics too good effect (Keestra et al. 2014; Rabelo et al. 2015). Thus, the aim of this study is to conduct a systematic review and meta-analysis to evaluate the effectiveness of systemic antibiotic therapy associated with periodontal treatment in smokers.


This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement with the focused question; “Do adjunctive antimicrobials improve the clinical outcome of non-surgical therapy (scaling and root planing [SRP]) in the treatment of periodontitis in smokers?”

The following inclusion criteria were applied:  Randomized controlled clinical trials; studies published in English; studies with smoker patients (at least 10 cigarettes per day for at least five years) diagnosed with chronic periodontitis; patients without significant systemic diseases ; aged between 30 and 70 years; not receive periodontal treatment in the last six months; used systemic antibiotic therapy associated with periodontal treatment; present the results of the test and control groups, and  assessments of clinical periodontal parameters such as probing depth (PD), bleeding on probing (BOP) and clinical attachment level (CA). Exclusion criteria were local antibiotic therapy and trials not published in English.

Two researchers independently selected and screened the articles. Data bases were searched from July 1994 to August 2016. The included databases were MEDLINE, Cochrane Controlled Clinical Trial Register, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, CINAHL, Science Direct, and ISI Web of Knowledge, Scopus, and manually searched relevant specialist journals. Quality assessment was undertaken using the Jadad scale.


The systematic Search found 3 papers out of 68 which fulfilled the inclusion criteria for meta-analysis. On the JADAD risk of bias assessment only 8/30 studies were evaluated as high quality.

Meta-analysis results (Primary outcomes)

Mean Difference Probing Depth (p = 0.0359   MD -0.32,   95% CI -0.50 – -0.14)
Mean Difference Clinical Attachment level (p = 0.0161   MD -0.22,   95% CI -0.39 – -0.06)
Mean Difference Bleeding on Probing (p = 0.446     MD -0.04,   95% CI -0.13– 0.06)

 Author’s Conclusion

“The results of our meta-analysis reveal the clinical benefits of systemic antibiotics as an adjunct to the non-surgical periodontal treatment of smokers. These clinical improvements, although statistically significant, appeared to be of little clinical relevance.”


In the discussion, the author goes to considerable length to explain the effectiveness for the adjunctive use of antibiotics in the periodontal treatment of smokers and to their credit also the lack of clinical relevance. There are three important points to be made here:

  • The degree of precision in the published mean difference of this paper is 0.005mm. The maximum precision possible with a standard periodontal probe is 0.5mm, and in the surgery the measurements are mostly taken as whole numbers. Mosteller described the issue this way:

“The number of significant figures gives a hint of accuracy. For example, 98.2o has three significant figures and might be regarded as correct to within 0.05o (One should not count on this level of accuracy.) Therefore, in these ambiguous circumstances, the author should tell what degree of accuracy is intended, as nearly as possible”(Mosteller 1992)


  • It is not an uncommon finding in primary research that the test groups and the trials time-frame are far too small to derive any precise/useful statistical results; this is something authors need to be addressed at the planning and protocol registration stage.


  • Additionally in the primary research the subjects continued to smoke throughout the duration of the trial, therefore it is hardly surprising there is no improvement in the results, the damaging effect of the smoking drowning out the benefit of the antibiotics. It is generally accepted that tobacco smoking remains the leading single risk to health in high-income North America and Western Europe by quite a large margin. (Lim et al. 2012).


Primary Paper

Assem, N.Z. et al., 2017. Antibiotic therapy as an adjunct to scaling and root planing in smokers: a systematic review and meta-analysis. Brazilian Oral Research, 31, pp.1–15. Available at:

Additional references

Dietrich, T. et al., 2015. Smoking, Smoking Cessation, and Risk of Tooth Loss: The EPIC-Potsdam Study. Journal of dental research, 94(10), pp.1369–75.

Keestra, J.A.J. et al., 2014. Non-surgical periodontal therapy with systemic antibiotics in patients with untreated chronic periodontitis: A systematic review and meta-analysis. Journal of Periodontal Research, (32), pp.689–706.

Lim, S.S. et al., 2012. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: A systematic analysis for the Global Burden of Disease Study 2010. The Lancet, 380(9859), pp.2224–2260.

Mosteller, F., 1992. Writing about numbers. In Medical uses of statistics. Boston: NEJM Books, pp. 375–89.

Rabelo, C.C. et al., 2015. Systemic antibiotics in the treatment of aggressive periodontitis. A systematic review and a Bayesian Network meta-analysis. Journal of Clinical Periodontology, 42(7), pp.647–657.

Zeng, J. et al., 2014. Reexamining the Association Between Smoking and Periodontitis in the Dunedin Study With an Enhanced Analytical Approach. Journal of Periodontology, 85(10), pp.1390–1397. Available at:





Dental implant placement into fresh extraction sockets

indexImmediate placement of dental implants into fresh extraction sockets has for some time been an established surgical technique. The theory is that it preserves alveolar ridge, reduces morbidity, and is more acceptable to the patient. However, there may also be disadvantages such as reduced implant survival, unfavourable changes in the hard/soft tissue and extended treatment times. To standardise the type of implant placement they have been classified into four types:


  • Immediate placement (type 1).
  • Early placement with soft tissue healing (type 2).
  • Early placement with partial bone healing (type 3).
  • Late placement (type 4).

The research question for this systematic review and meta-analysis was: ‘‘Do immediately inserted implants perform similarly to implants that are inserted into a healed socket?’’


This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and registered with PROSPERO.

The population (P) was patients who had undergone osseointegrated implant insertion into fresh extraction sockets (I) or healed sockets (C). The primary outcome (O) evaluated was implant survival rate. Marginal bone loss, primary implant stability, and soft tissue changes were considered secondary outcomes. The following inclusion criteria were applied: Randomised controlled or prospective studies in English. More than five implants per group with a minimum of six months follow-up. Exclusion criteria were animal and in vitro studies, simple evaluations without comparators or analyses of loading protocols.

Two researchers independently selected and screened articles PubMed/Medline, Embase, and Cochrane databases and manually searched relevant specialist journals. Quality assessment was undertaken using the Jadad scale and Cochrane Collaboration’s tool for assessing risk of bias.


  • The systematic Search found 30 papers out of 3049 which fulfilled the inclusion criteria. On the Jadad risk of bias assessment only 8/30 studies were evaluated as high quality.
  • Meta-analysis results (Primary outcomes)
Relative risk(95% Confidence Interval) Probability
Survival favours healed sockets 2.49, (1.44 – 4.29) p = 0.001
Type 1 compared with type 2 1.45, (0.53 – 3.98). p = 0.47
Type 1 compared with type 3 5.25, (1.67 – 16.49) p = 0.005
Type 1 compared with type 4 2.86, (1.22 – 6.70) p = 0.02
  • There were no statistical differences in the secondary outcomes.


The authors concluded:-

In conclusion, immediate implant insertion should be performed with caution because implant survival rates are significantly lower than with implants inserted into healed sockets.


My intuition tells me that the authors may have the right answer but the evidence they present does not support this for various methodological reasons. The major problem is that the survival data is of relatively short duration and heterogeneous with a mean follow-up being 24 months, median 18 months and a mode  of 12 months.

Clinicians mostly will only be interested in long-term data (60 months plus). Focusing on just these longer-term studies papers in the review just leaves three papers (Cooper et al 2014, Polizzi et al 2000 and Raes et al 2016) , so a second Raes paper (Raes et al 2013)  with a stated 52 months follow up and the 2015 Oxby paper with 55 months follow up were reviewed and meta-analysed.

Looking at these research papers with the longest follow-up is simpler to appraise than the 30 the authors included. Full texts were obtained and the following conclusions made:

  • The Raes paper (Raes et al 2013) states only 52 weeks follow-up not 52 months as in the review, which is quite important if we are meant to be looking a survival studies.
  • In the Polizzi paper (Polizzi et al 2000) there is no randomisation between the healed and fresh extraction sockets.
  • The Oxby paper reads as though it is retrospective review and 25% of the sample was excluded after implant placement as the loading protocol exceeded 60 days (this group could possibly contain the failures?). Not all the implants were reviewed at 60 months (38/182 were reviewed between 36-48 months, 114/182 between 49-60 months and 30/182 between 60-63 months).
  • Lost to follow (LTF) up in the studies varies from 13% – 40%. The authors classified the LFT patients as missing completely at random to optimise the survival data.

The 2013 Raes paper was therefore excluded as the follow-up was too short, and the Oxby paper as a retrospective study (exclusion criteria). The remaining studies were included in a meta-analysis. Group a. is the data as published in the systematic review and Group b. where LTF is considered in the calculations as a failure.

Fig.1 shows the new risk ratio (RR) for the long-term data has reduced from 2.49 to 1.28. If missing data is considered as a failure the RR drops to 1.06 (Fig. 2). An interesting observation is that the risk difference for Group a (Fig. 3) is 0.01.

Fig. 1. Forest plot for the event ‘60-month implants survival rates’ for Group a.


Fig. 2. Forest plot for the event ‘60-month implants survival rates’ for Group b.


Fig. 3. Forest plot for the Risk Difference ‘60 month implants survival rates’ for Group a.


In conclusion from this data there is no difference between techniques, possibly due to the ability to select cases rather than a true randomisation. One interesting point is that long-term survival for fresh v. healed was 94.4 and 96.9; if missing data is considered a failure 5-year survival drops by a further 15%. As usual the truth lies somewhere in between.


Primary paper

Mello CC, Lemos CAA, Verri FR, Dos Santos DM, Goiato MC, Pellizzer EP.Immediate implant placement into fresh extraction sockets versus delayed implants into healed sockets: A systematic review and meta-analysis. Int J Oral Maxillofac Surg. 2017 May 3. pii: S0901-5027(17)31361-9. doi: 10.1016/j.ijom.2017.03.016. [Epub ahead of print] Review. PubMed PMID: 28478869.

Other references

Cooper LF, Reside GJ, Raes F, Garriga JS, Tarrida LG, Wiltfang J, Kern M, De Bruyn H. Immediate provisionalization of dental implants placed in healed alveolar ridges and extraction sockets: a 5-year prospective evaluation. Int J Oral Maxillofac Implants. 2014 May-Jun;29(3):709-17.

Polizzi G, Grunder U, Goené R, Hatano N, Henry P, Jackson WJ, Kawamura K, Renouard F, Rosenberg R, Triplett G, Werbitt M, Lithner B. Immediate and delayed implant placement into extraction sockets: a 5-year report. Clin Implant Dent Relat Res. 2000;2(2):93-9.

Raes S, Raes F, Cooper L, Giner Tarrida L, Vervaeke S, Cosyn J, De Bruyn H. Oral health-related quality of life changes after placement of immediately loaded single implants in healed alveolar ridges or extraction sockets: a 5-year prospective follow-up study. Clin Oral Implants Res. 2017 Jun;28(6):662-667. Epub 2016 May 22.

Oxby G, Oxby F, Oxby J, Saltvik T, Nilsson P. Early Loading of Fluoridated Implants Placed in Fresh Extraction Sockets and Healed Bone: A 3- to 5-Year Clinical and Radiographic Follow-Up Study of 39 Consecutive Patients. Clin Implant Dent Relat Res. 2015 Oct;17(5):898-907.

Raes F, Cosyn J, De Bruyn H. Clinical, aesthetic, and patient-related outcome of immediately loaded single implants in the anterior maxilla: a prospective study in extraction sockets, healed ridges, and grafted sites. Clin Implant Dent Relat Res. 2013 Dec;15(6):819-35.

Dental Elf – 2 August 2017

Dental Elf -12th Dec 2014

Mandibular fractures: the influence of third molars

fractued jaw

The prevalence of mandibular fractures among facial fractures is high, reaching 76% of all facial fractures. The mandibular regions that fracture most frequently are the mandibular condyles (56.5%), mandibular symphysis (45.0%), body (25.5%), and angle (16.5%). The locations of mandibular fractures are related directly to the fragility of these bone areas: the condyle is the mandibular area with the lowest bone thickness and is most frequently fractured.

The third molar, when present, may generate a weak area in the mandibular angle and predispose this region to fracture. The authors wished to investigate this relationship.


This systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

The population comprised patients with mandibular fractures; the exposure was the presence or absence of a third molar (3M) and the different positions of the third molar; the comparison was with other mandibular fractures; the outcome was an angle fracture.

The following inclusion criteria were applied in this systematic review: observational studies (cross-sectional, case– control, and prospective and retrospective cohort studies. Exclusion criteria were iatrogenic jaw fracture from surgery and fracture in patients with diseases of bone metabolism (osteopenia and osteoporosis).

The electronic survey was conducted by two authors in the PubMed, Scopus, Web of Science, Cochrane Library, and VHL (Virtual Health Library; BIREME (PAHO/WHO)) databases, and included publications up to January 2016, without language restriction.

The assessment of the quality of the studies included was performed using the Newcastle–Ottawa scale (NOS) for case-control studies and a modified NOS for cross-sectional studies.


The systematic Search found 35 papers out of 704 which fulfilled the inclusion criteria. There were 22 case-control studies and 13 cross-sectional. 28 out of the 35 were used in the meta-analysis.

On the risk of bias assessment 5 case controlled and 2 cross sectional studies scored 8/9 on the Newcastle-Ottawa scale.

Meta-analysis results expressed as an Odds Ratio (OR)

Odds Ratio 95% CI Heterogeneity (I2)
Odds of mandibular fracture (angle) than any other mandibular fracture if 3M’s present. 3.27 2.75-4.16 81.3
Mandibular angle fracture in the presence of a 3M 3.83 3.02-4.85 83.1
Comparing a Pell and Gregory B v. A+C 1.44 1.06-1.96 87.2
Comparing a Pell and Gregory A v. B+C 0.60 0.45-0.81 87.1
Comparing a Pell and Gregory C v. A+B 1.19 0.57-2.46 96.1


The authors concluded: –

The results suggest that the presence of the third molar increases the chance of angle fracture by 3.27 times and that the most favourable positions of the third molar for angle fracture are classes B and II, whilst classes A and I act as protective factors.


There are three areas that need to be taken into account when considering the authors result and conclusions.

The first point is that angle of jaw fractures are not common. In a recent paper looking at mandibular jaw fractures presenting at a London teaching hospital the approximate annual incidence for angle fracture was 17 in 100,000. About half the individuals present with 2 mandibular fractures and the male: female ratio was 6.6:1(Rashid et al. 2013).

Secondly the cause of mandibular fractures varies with geographical location. Roughly 90% of fractures in the UK data were due to interpersonal violence and in Asia/India the same proportion is due to motor vehicle accidents. Fractures resulting from violence were most commonly associated

with the angle region while those related to road traffic accidents usually involve the condyle, body and parasymphysis  (Nasser et al. 2013).

Thirdly the results are expressed as an odds ratio(OR). Even though OR is a legitimate way to express an effect size especially in regard to case-control studies it may not have been the best way to convey the information in this case. When events are rare the difference between odds and risk are small but when events are common (>20%) this difference can become large, in this review it’s about 60%. From the ‘analysis = fracture forest plot in Fig.3’ the OR is 4.15 (i.e. out of 5 jaw fractures 4 will be at the angle) but when this is converted to risk ratio (RR) we get a value of 1.60 (i.e. The presence of a 3M increases the risk by 60%).

Though there is no doubt that the presence of 3M increases the chance of a mandibular angle fracture the results need to be interpreted with caution due to both high confounding and heterogeneity.


The Dental Elf

Primary paper

Armond ACV, Martins CC, Glória JCR, Galvão EL, Dos Santos CRR, Falci SGM.Influence of third molars in mandibular fractures. Part 1: mandibular angle-ameta-analysis. Int J Oral Maxillofac Surg. 2017 Jun;46(6):716-729. doi:10.1016/j.ijom.2017.02.1264. Epub 2017 Mar 11. Review. PubMed PMID: 28291569.

Other references

Nasser M, Pandis N, Fleming PS, Fedorowicz Z, Ellis E, Ali K. Interventions for the management of mandibular fractures. Cochrane Database Syst Rev. 2013 Jul 8;(7):CD006087. doi:10.1002/14651858.CD006087.pub3. Review. PubMed PMID:23835608.

Rashid A, Eyeson J, Haider D, van Gijn D, Fan K. Incidence and patterns of mandibular fractures during a 5-year period in a London teaching hospital. Br J Oral Maxillofac Surg. 2013 Dec;51(8):794-8. doi: 10.1016/j.bjoms.2013.04.007.Epub 2013 Jun 2. PubMed PMID: 23735734.

Dental Elf – 21st May 2013