The angular bony defect as indicator of further alveolar bone loss

The aim of the present retrospective study was to evaluate alterations of the alveolar bone level over a 10-year period at tooth sites with "angular" and "even" patterns of bone loss, in subjects who were not exposed to systematic periodontal therapy. A further objective was to evaluate whether the presence of an angular defect can serve as a predictor of additional bone loss. 201 subjects in ages 25-70 years were examined radiographically on 2 occasions 10 years apart. 194 were dentate on the 2nd examination. The radiographic bone height at the mesial and distal aspect of all teeth was assessed by measuring the distance between the cemento-enamel junction and the bone crest. The morphologic pattern of alveolar bone loss at baseline was assessed for each tooth site. Angular defects were classified as degree 1, 2 and 3, according to increasing defect depth. The change in periodontal bone height over the 10-year period was calculated for each site. The results demonstrated an increased frequency of tooth loss among teeth showing presence of an angular bony defect at baseline; whereas 13% of the teeth with an even pattern of bone loss were lost between the 2 examinations, this proportion was 22%, 46% and 68% for teeth with an angular defect of degree 1, degree 2 and degree 3, respectively. Longitudinal bone loss of greater than or equal to 2 mm occurred more often among sites showing an angular defect when compared to sites with an even alveolar bone morphology.(ABSTRACT TRUNCATED AT 250 WORDS)     

Periodontal status in relation to age and tooth type

The purpose of the present study was to assess by radiographic means the pattern of destructive periodontal disease within the dentition of individuals of different ages. Full-mouth series of intra-oral radiographs from 531 dentate individuals aged 25-75 years were examined with respect to number and type of remaining teeth, location of the alveolar bone in relation to the cemento-enamel junction and presence of angular bony defects. The assessments of alveolar bone levels and angular bony defects were performed at the approximal surfaces of all teeth present. The results showed that although most individuals had experienced a reduction in alveolar bone height with age, only a small number of subjects had developed advanced breakdown of the periodontium. Hence, pronounced bone loss was observed in only 11% of the subjects and was non-existent in ages below 35 years. 23% of the individuals accounted for 3/4 of the total number of sites with bone level values (bone loss) of greater than or equal to 6 mm. Out of the total number of tooth sites examined, 28% showed no bone loss, while 13% demonstrated pronounced periodontal tissue breakdown. Angular bony defects were found at 8% of all teeth examined and were most frequent at the maxillary first premolars. Teeth in the incisor regions consistently showed the highest frequency of advanced alveolar bone loss and the lowest frequency of normal tissue support, while corresponding figures for teeth in the molar regions were found to be the opposite. However, molars were the most frequently missing teeth.     

Periodontal disease progression in teenagers with no preventive dental care provisions

Periodontal disease progression was studied on bitewing radiographs taken at baseline and after 1 year for a group of 422 teenagers who had no access to preventive or therapeutic dental services. Subjects exhibiting one or more proximal surfaces of 1st molars with longitudinal bone loss and/or with vertical bone defects at the 2nd examination were regarded as periodontal risk patients. This group then underwent a further examination in which periapical radiographs of the anterior teeth were taken and the clinical loss of attachment at the proximal surfaces of all teeth was assessed. Subsequently, the radiographic and clinical states of the risk group were compared. Most sites exhibiting bone loss during the study period displayed vertical bone defects and were largely confined to mesial surfaces of first molars. 24% of sites showing alveolar bone loss at baseline demonstrated further loss 1 year later. Girls exhibited significantly higher prevalence and incidence of sites showing bone loss than did boys. 24 children (5.7%) were regarded as periodontal risk patients. The radiographs significantly underestimated the prevalence of periodontal destruction in the risk group as compared to clinical measurements. It was concluded that using 2 bitewing radiographs is adequate for the identification of risk subjects, and that periodontal progression in adolescence occurs mainly in the first molar region and may affect girls more often than boys.     

Radiographic alveolar bone morphology and progressive periodontitis

1 Background

This study evaluated the relationship between radiographic crestal alveolar bone morphology and progressive periodontitis.

2 Methods

A total of 1,356 posterior interproximal sites in 56 adults treated for chronic periodontitis and receiving systematic 3‐month maintenance care were scored for angular or horizontal marginal bone morphology, as well as for alveolar crestal lamina dura, on radiographs obtained at baseline of a 30‐month post‐treatment period. Semi‐annually, the study patients were clinically evaluated for progressive periodontitis. Logistic regression analysis assessed baseline parameters to progressive periodontitis over the 30‐month post‐treatment period.

3 Results

Progressive periodontitis was detected at 33 (2.4%) posterior interproximal sites in 20 (35.7%) patients. Sites with post‐treatment angular bony defects developed progressive periodontitis more frequently (14.7%) than sites with a horizontal bone topography (1.8%). Angular bony defects (odds ratio = 10.6) and periodontal probing depths ≥5 mm (odds ratio = 4.2) were identified as statistically significant independent predictors of progressive periodontitis at posterior interproximal sites. Angular bony and horizontal lesions with intact radiographic lamina dura revealed an absence of progressive periodontitis through 24 months.

4 Conclusions

Post‐treatment presence of angular bone morphology and periodontal probing depths ≥5 mm significantly increased risk of progressive periodontitis at posterior interproximal sites. Sites of all morphology and probing depth that displayed radiographic crestal lamina dura at post‐treatment baseline exhibited clinical stability for ≥24 months.     

Long-term maintenance of patients treated for advanced periodontal disease

The aim of the present investigation was to evaluate the periodontal conditions of a group of patients who, following active treatment of extremely advanced periodontal disease, had been maintained for 14 years in a well-supervised maintenance care program. The present sample included 61 subjects out of an initial group of 75 individuals who in 1969 were referred to and treated by the authors. Following an initial examination, the patients were given detailed instructions in proper plaque control measures and were subjected to scaling and root planning and surgical elimination of pathologically deepened pockets. After the termination of the active treatment phase, the patients were placed in a maintenance care program including recall appointments every 3-6 months. At the initial examination, immediately after the completion of the active treatment phase and then once a year, all patients were examined regarding oral hygiene, gingival conditions, probing depths and clinical attachment levels. In addition, the interproximal alveolar bone height was determined from full mouth radiographs obtained before active treatment, at the completion of active therapy and 1, 3, 5, 8, 10, 12 and 14 years after treatment. The results from the repeated examinations demonstrated that treatment of advanced forms of periodontal disease resulted in clinically healthy periodontal conditions and that this state of "periodontal health" could be maintained in most patients and sites over a period of 14 years. It was also demonstrated that the treatment and maintenance programs described were equally effective in young and older patients. The individual mean values describing probing depths, attachment levels, and bone heights did not vary significantly over the 14 years of observation. A more detailed analysis of the data revealed, however, that a small number of sites in a few patients lost a substantial amount of attachment. This attachment loss occurred at different time intervals during the course of the maintenance period. Thus, 43 surfaces in 15 different patients were exposed to recurrent periodontal disease of a significant magnitude. This recurrent inflammatory periodontal disease caused the loss of 16 teeth in 7 different patients during the maintenance period. The data reported question the validity of using individual mean values to describe alterations of the periodontal conditions during maintenance following active periodontal therapy.     

Assessment of alveolar bone levels from intraoral radiographs in subjects between ages 15 and 94 years seeking dental care

Abstract. Studies have shown that <20% of the US population has periodontal disease. Studies of radiographs have shown that alveolar bone loss increases with age. Bone loss assessed from intraoral radiographs describing 10,282 teeth from 416 subjects seeking dental care during a 3 month period at the University of Washington were studied. The mean age of the subjects was 47.2 years (SD±15.2). The youngest subjects (15–24) had on average 29.6 teeth (SD±2.2) and the oldest subjects (75–94) 19.3 teeth (SD±6.6). This difference was statistically significant ( F =16.57. p <0.00l). No association was found between alveolar bone loss (CEJ-ABC). and TMD symptoms. Smoking was significantly associated with both general bone loss (CEJ-ABC) ( x ²=114.9. p <0.0001), and vertical bone defects (angular) ( x ²= 101.8. p <0.0001). In this study population (15–94 years), alveolar bone loss progressed as defined by the slope (β=0.29) between age 15–34, but was almost flat from age 50 years (β=0.04). The data suggested an overall rate of alveolar bone loss of 0.02 mm per year. Stepwise multiple regression analysis showed that smoking was the primary factor in bone loss ( t =7.7, p <0.0001), followed by age ( t =7.0. p<0.001) and gender ( t =3.0. p <0.01). TMD symptoms could not explain the presence and severity of horizontal or vertical defects. If the CEJ-ABC distance above the mean plus 2× the SD was used as the cutoff value to define abnormal bone levels. 10.9% of the younger (15–45 years), and 10.7%) of the older subjects (50–94) had significant alveolar bone loss. 73.9% of the younger and 100% of the older subjects with such extent of alveolar bone loss were smokers.     

Detection of active alveolar bone destruction in human periodontal disease by analysis of radiopharmaceutical uptake after a single injection of 99m-Tc-methylene diphosphonate

Previous studies have shown that, following a single injection of 99m-Tc-MDP, measurement of bone-seeking radiopharmaceutical uptake can detect "active" alveolar bone loss due to periodontal disease in beagle dogs, as determined by radiographs taken at the time of, and several months after, the nuclear medicine procedure. The efficacy of this diagnostic test. however, had not been assessed in human periodontal disease. The ability of a single bone-seeking radiopharmaceutical uptake examination to detect "active" alveolar bone loss due to periodontal disease in human patients was assessed by comparing a single uptake measurement to the rate of bone loss determined from serial radiographs taken over a 6-month period. Uptake was expressed as a ratio of the cpm from the alveolar bone divided by the cpm from the non-tooth supporting bone of the nuchal crest. High uptake ratios were associated with "active" loss and low uptake ratios were associated with little if any change in alveolar bone height (p < 0.001). The nuclear medicine examination was an accurate detector of periodontal disease activity in nearly 80% of the individual teeth studied. These data indicate that high bone-seeking radiopharmaceutical uptake ratios may be pathognomonic of active bone loss in human periodontal disease.     

引导牙周组织再生在伴牙槽骨缺损牙再植术中应用的回顾性研究

目的 :回顾分析配合引导性组织再生术 (guidedtissueregeneration ,GTR)治疗对伴牙槽骨缺损的脱位再植牙的临床疗效的影响 ,为引导牙周组织再生的进一步研究提供经验。方法 :收集 1996年～ 2 0 0 3年间伴牙槽骨缺损、再植术中配合了GTR术治疗的完整病历资料 ,对其临床治疗情况及近远期疗效作回顾性研究分析。结果 :共收集到 2 3份符合条件的病历 (6 4颗再植牙 ) ,疗效分析结果表明 ,患牙术后 12个月探诊深度均显著减少 ,附着水平均显著获得 ;无论脱位时间长短 ,术后牙松动、牙根吸收和失牙的发生率均较高。伤后 6h内就诊脱位牙直接再植后 ,牙髓坏死率 77.5 % ,牙根吸收和失牙率与伤后就诊超过 6h组有显著性差异 (P <0 .0 1)。结论 :伤后就诊时间影响再植牙治疗效果 ,配合单纯GTR治疗 ,伴牙槽骨缺损的脱位再植牙的远期疗效仍然较差 ,利用GTR技术促进牙周组织再生特别是促进牙周缺损的再生需要进一步的基础与临床研究。     

Distribution of periodontal disease in a Swedish adult population 1973, 1983 and 1993

Abstract. The aim of this study was to compare changes in periodontal status in a Swedish poplation over a period of 20 years. Cross-sectional studies were carried out in Jönköping County in 1973, 1983, and 1993. Individuals were randomly selected from the following age groups: 20, 30, 40, 50, 60, and 70 years. A total of 600 individuals were examined in 1973, 597 in 1983, and 584 in 1993. The number of dentate individuals was 537 in 1973, 550 in 1983, and 552 in 1993. Based on clinical data and full mouth intra-oral radiographs, all individuals were classified into 5 groups according to the severity of the periodontal disease experience. Individuals were classified as having a healthy periodontium (group 1). gingivitis without signs of alveolar bone loss (group 2), moderate alveolar bone loss not exceeding 1/3 of the normal alveolar bone height (group 3), severe alveolar bone loss ranging between 1/3 and 2/3 of the normal alveolar bone height (group 4), or alveolar bone loss exceeding 2/3 of the normal bone height and angular bony defects and/or furcation defects (group 5). During these 20 years, the number of individuals in groups 1 and 2 increased from 49%. in 1973 to 60% in 1993. In addition, there was a decrease in the number of individuals in group 3, the group with moderate periodontal bone loss. Groups 4 and 5 comprised 13% of the population and showed no change in general between 1983 and 1993. The individuals comprising these groups in 1993, however, had more teeth than those who comprised these groups in 1983; on the average, the individuals in disease group 4 had 4 more teeth and those in disease group 5, 2 more teeth per subject. ID 1973, these 2 groups were considerably smaller, probably because of wider indications for tooth extractions and fewer possibilities for periodontal care which meant that many of these individuals had become edentulous and were not placed in a group. Individuals in groups 3, 4, and 5 were subdivided according to the number of surfaces (%) with gingivitis and periodontal pockets (≥4 mm). In 1993, 20%, 42%, and 67% of the individuals m groups 3, 4, and 5 respectively were classified as diseased and in need of periodontal therapy with >20% bleeding sites and >10% sites with periodontal pockets ≥4 mm. In conclusion, an increase in the number of individuals with no marginal bone loss and a decrease in the number of individuals with moderate alveolar bone loss can be seen. The prevalence of individuals in the severe periodontal disease groups (4, 5) was unchanged during the last 10 years; however, the number of teeth per subject increased.     

Digital subtraction radiographic analysis of GTR in human intrabony defects

The relationship between radiographic crestal alveolar bone mass and changes in clinical periodontal attachment level following guided tissue regeneration (GTR) was evaluated in this retrospective study. A total of 12 intrabony two- or three-walled defects and 12 adjacent nondiseased proximal sites in 10 nonsmoking adult subjects received subgingival debridement and GTR using resorbable (Resolut; five sites) or nonresorbable (Gore-Tex; seven sites) barrier membranes. At a mean of 48.8 months posttreatment, clinical periodontal attachment level alterations were measured, and crestal alveolar bone mass changes on digital subtraction radiographic images derived from serial periapical radiographs were analyzed to correct for between-film geometric and contrast density differences. Intrabony defects exhibited a mean clinical periodontal attachment level gain of 2.3 +/- 0.4 mm, in contrast to a mean loss of 0.5 +/- 0.2 mm in adjacent nondiseased interproximal sites. Digital subtraction radiography revealed an increase in crestal alveolar bone mass at all intrabony sites treated with GTR and a decrease in three of the adjacent nondiseased sites. Site-based analysis yielded an odds ratio of 36 (P < .001) for the association between radiographic increases in crestal alveolar bone mass and clinical periodontal attachment level gains of > or = 2 mm. These results suggest a strong concordance between digital subtraction radiographic assessments of crestal alveolar bone mass and clinical periodontal attachment level in evaluating the long-term effects of GTR at human interproximal intrabony defects.     

The significance of alveolar bone in periodontal disease

The periodontal conditions in 19 patients with unilateral cleft lip, alveolus and palate (CLAP) and in 6 patients with bilateral CLAP, were evaluated in 1979 and re-examined in 1987. During these 8 years, these patients were not subjected to any professionally supervised maintenance care program. Pronounced plaque accumulation and high frequency of gingival units exhibiting bleeding on probing were noted in the majority of the patients both in 1979 and 1987, documenting inadequate oral hygiene standards with resulting inflammatory reactions of the periodontal tissues. Progression of periodontal disease over time was assessed as loss of clinical attachment and loss of alveolar bone height. The periodontal destruction was not found to be more severe at cleft sites with a long connective tissue attachment than at control sites not affected by cleft defects. It was concluded that sites with a long supracrestal connective tissue attachment do not seem to be more prone to periodontal destruction, induced by bacterial infection, than sites with a normal length of the supraalveolar fibrous attachment. The results also show that the alveolar bone height, as visualized in radiographs at sites with alveolar defects, is of limited value for the diagnosis of the degree of periodontal destruction at such sites.     

Prognostic factors for alveolar regeneration: bone formation at teeth and titanium implants

OBJECTIVES: There is a limited understanding of the effect of defect characteristics on alveolar bone healing. The objectives of this study were to assess the effect of alveolar bone width and space provision on bone regeneration at teeth and titanium implants, and to test the hypothesis that the regenerative potentials at teeth and implants are not significantly different. METHODS: Critical size, 5-6-mm, supra-alveolar, periodontal defects were surgically created in 10 young adult dogs. Similarly, critical size, 5-mm, supra-alveolar, peri-implant defects were created in four dogs. A space-providing expanded polytetrafluoroethylene device was implanted for guided tissue regeneration/guided bone regeneration. The animals were euthanized at 8 weeks postsurgery. Histometric analysis assessed alveolar bone regeneration (height) relative to space provision by the device and the width of the alveolar crest at the base of the defect. Statistical analysis used the linear mixed models. RESULTS: A significant correlation was found between bone width and wound area (r=0.55892, p<0.0001). Generally, bone width and wound area had statistically significant effects on the extent of bone regeneration (p<0.0005 and p<0.0001, respectively). Bone regeneration was linearly correlated with the bone width at periodontal (p<0.001) and implant (p=0.04) sites, and with the wound area at periodontal (p<0.0001) and implant (p=0.03) sites. The relationships of bone regeneration with these two variables were not significantly different between teeth and implants (bone width: p=0.83; wound area: p=0.09). When adjusted for wound area, bone regeneration was significantly greater at periodontal than at implant sites (p=0.047). CONCLUSIONS: The horizontal dimension of the alveolar bone influences space provision. Space provision and horizontal dimension of the alveolar bone appear to be important determinants of bone regeneration at teeth and implants. The extent of alveolar bone formation at implant sites is limited compared with that at periodontal sites.     

Regeneration of alveolar bone following surgical and non-surgical periodontal treatment

The purpose of this investigation was to examine the regeneration of alveolar bone following surgical and non-surgical periodontal treatment. A total of 16 patients who had advanced periodontitis and demonstrated angular bony defects on radiographs participated in the study. After the initial examination, they received instruction in oral hygiene and had their teeth thoroughly scaled. When the individual patient at 2 succeeding appointments had plaque on less than 20% of the tooth surfaces, one maxillary and one mandibular quadrant was treated with the modified Widman flap procedure while one of the remaining quadrants was treated with the reverse bevel flap procedure. The last quadrant was treated with root planing under local anesthesia. None of these procedures included bone contouring. Following treatment, the patients were recalled every 2 weeks for professional tooth cleaning. Radiographs taken 12 months following treatment revealed that only minor changes in the bone level had occurred in areas with horizontal bone loss following the various treatment modalities. Following the modified Widman flap procedure, however, a statistically significant coronal regrowth of bone (0.5 mm) had occurred in angular bony defects. The majority of the angular bony defects persisted following all 3 treatment modalities.     

The angular bone defect and its relationship to trauma from occlusion and downgrowth of subgingival plaque

Sixty-four sets of human teeth were collected with the aim of evaluating the role of trauma from occlusion in the etiology of destructive periodontal disease. Before the jaws were taken out, a careful bite analysis was carried out. After fixation of the jaws, impressions were taken and plaster of Paris models were made. Finally, a set of 14 radiographs were taken. On the basis of the "clinical" records postmortem, the study models and the radiographs, the jaws were sectioned. Only mesio-distal sections were included in the present analysis. The total number of interdental spaces examined was 106. The following observations were made: 1. Before any loss of periodontal fiber attachment has taken place, the configuration of the interdental septum is entirely dependent on the location of the cemento-enamel junction (CEJ) of the two neighboring teeth. The alveolar crest does not approach the apical border of the junctional epithelium closer than about 1 mm. Thus, if the CEJ is located at different levels on two neighboring teeth, the marginal termination of the interdental septum will be oblique, forming an acute angle with the "lowest" tooth. 2. Loss of periodontal fiber attachment could invariably be related to the apical growth of subgingival plaque, and downgrowth of plaque was always associated with an inflammatory process which involved lysis of the attachment fibers within a distance varying between 0.2 and 1.8 mm from the apical border of the plaque. Subsequently, the JE proliferated down to cover the denuded root surface. 3. Reduction in height of the alveolar crest could also be related to the downgrowth of plaque. The distance from plaque to bone was never found to be less than 0.5 mm and never more than 2.7 mm. The configuration of the interdental septum always seemed to be determined by the level of the plaque on the two neighboring tooth surfaces. Thus, if the plaque had reached the same level on both sides, the crest of the interdental septum assumed a horizontal outline; if plaque had proliferated down to different levels, the crest of the interdental septum was oblique and an angular defect hereby established. 4. In the present material no evidence was found to indicate that functional (traumatic) forces can act as a co-factor in the causation of angular defects. In fact, such defects were found equally often adjacent to "nontraumatized" as to "traumatized" teeth. 5. Infrabony pockets were invariably associated with downgrowth of subgingival plaque.     

Assessment of bone loss in periodontitis from panoramic radiographs

Bone loss in chronic periodontitis was assessed from panoramic radiographs by direct measurement from the cemento-enamel junction (CEJ) and by measuring the proportion of the tooth length supported by bone. Mesial and distal bone levels of all available teeth were assessed for 50 patients aged 30-39 years referred for periodontal treatment. 85% and 74% of surfaces were measurable by the proportional and direct techniques, respectively. 27% of surfaces had no bone loss according to the proportional score, whereas 22% had a CEJ to alveolar bone distance of less than 2 mm. In addition, over half the surfaces with a proportional bone loss score of zero had a CEJ to alveolar bone distance of 2 mm or more, and for each proportional bone loss score, there was considerable overlap in the CEJ to alveolar bone distances recorded. The validity of the CEJ to alveolar bone measurements was established by comparison with direct measurements at periodontal surgery. The results support the use of direct measurement from the CEJ to alveolar bone rather than the assessment of the proportion of the tooth length within the bone when investigating bone loss from panoramic radiographs. This population of 30-40-year-old periodontal patients had a mean of 50% of sites with a CEJ to alveolar bone distance of 3 mm or more, and at such sites, there was a mean additional bone loss of 2.1 mm.     

Bone loss following periodontal therapy in subjects without frequent periodontal maintenance

The longitudinal effects of periodontal therapy in patients without a frequent periodontal maintenance program have been minimally documented. In this study we used Duckworth's modification of the Schei Ruler Technique to assess the difference in bone level around individual teeth treated for periodontal disease in subjects receiving infrequent posttherapy maintenance (less than or equal to 1 time/year). Crestal bone height differences were evaluated using the initial presenting series of long cone parallel radiographs of 23 subjects with their subsequent posttherapy analogous radiographic series taken 5.4 +/- 2.9 years later. Bone loss was defined as a reduction in the alveolar crest of greater than 50% of the radiographic crown height which corresponds to approximately 4 mm in posterior and 5 mm in anterior teeth. The loss for each tooth was expressed as a per cent of the measured height of the crown after conversion from millimeters using the mean crown-root ratio for each tooth. We found increased alveolar bone loss and tooth loss in subjects examined posttherapy when compared with conditions present when each subject initially presented for periodontal treatment. Our data suggest that molar teeth are more at risk than incisors and cuspids and that a lack of periodontal maintenance care and inadequate plaque control contribute to progressive bone loss following treatment.     

Proximal bone loss adjacent to periodontally "hopeless" teeth with and without extraction

Extraction of teeth with severe attachment loss ("hopeless" teeth) is common practice in the dental office. Recent evidence questions the validity of this approach. The purpose of the present study was to examine the alveolar bone changes adjacent to "hopeless" teeth with and without extraction. A total of 145 teeth from 129 patients were included in this retrospective study. Teeth were defined as "hopeless" when Class III furcation involvement was present, or when alveolar bone loss exceeded 50%. Patients were pooled into two groups: A, 82 "hopeless" teeth (71 patients) that were retained throughout the experimental period, and B, 63 "hopeless" teeth (58 patients) that were extracted. The average observation period was 4 years with a minimum of 2 years. Alveolar bone changes were measured as a percentage of the anatomic root (radiographic apex-CEJ) using a Schei ruler. Results revealed significantly greater bone loss adjacent to teeth flanking retained "hopeless" teeth, 3.12% per year, at a rate 10 times that of the 0.23% annual bone loss in teeth flanking "hopeless" teeth that were extracted (P less than 0.0001). This study confirms that without periodontal treatment, the retention of teeth with severe periodontal breakdown has a negative effect on the adjacent teeth.     

Periodontal disease morbidity quantification. I. Optimal selection of teeth for periodontal bone loss surveys

The assessment of alveolar bone loss with bite-wing radiographs is attractive because bite wings are relatively convenient, inexpensive, and available. The choice of teeth used influences the validity of global bone loss assessments based on partial mouth measurements. The objective of this study was to validate periodontal bone loss indices based on a few teeth. The mandibular posterior teeth were considered as a basis for abbreviated indices. The optimum number of teeth included was evaluated, and the utility of abbreviated indices was determined experimentally. The teeth from 75 skulls were measured from the cemento-enamel junction (CEJ) to the alveolar bone at six locations per tooth. The subsets of teeth which best represent the average whole mouth bone loss were found with all-possible-subsets regression analysis. Bone loss data from 179 prehistoric skulls were used to test the validity of selected teeth indices. Bone loss measurements from the mandibular posterior areas were representative of full-mouth bone loss measurements. Mandibular second premolars plus any other mandibular posterior teeth were the optimal combination of tooth for an abbreviated index. This subset is suitable for use with bite-wing radiographs.     

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??Abstract??Objective To study the effect of smoking on alveolar bone defect in patients with chronic peridontitis. Methods Select thirty patients respectively in smoking and non-smoking patients with chronic periodontitis??who are scanned by cone beam CT??CBCT??. Florida probe is applied to measure the PD and AL of all the teeth??including teeth's mesial??distal??buccal??lingual??. NNT software is applied to measure the average degree of alveolar bone defects in different regions??incisor area??canine area??premolar area and molar area??including teeth's mesial??distal??buccal??lingual??. Results The periodontal probing depth and attachment loss level had no significant difference??P > 0.05??in smoking group and non-smoking group??smoking group's alveolar bone defect degree was more serious than non-smoking group??the difference being statistically significant??P < 0.05??. Compared with the non-smoking group??alveolar bone defects in smoking group in each site of the same teeth were more serious??the difference being statistically significant??P < 0.05??. In two groups??the alveolar bone defect of canine area was the mildest??the most serious part of the alveolar bone defect in molar area??P < 0.05??. The alveolar bone defect had significant differences in smoking group among different sites of the same teeth??P < 0.05????while the most serious part in maxillary molars palatal. In smoking group??except for the distal sites of mandibular molar area and buccal and lingual sites of mandibular incisor area??the alveolar bone defect of maxillary teeth was more serious than mandibular teeth??the difference being statistically significant??P < 0.05??. In non-smoking group??the alveolar bone defect of the same site in different teeth showed a decreasing trend from the molar area to the canine area. But the alveolar bone defect of each point in mandibullar incisor area was significantly higher than maxillary incisor area??the difference being statistically significant??P < 0.05??. Conclusion In chronic periodontitis patients??the alveolar bone defect of smokers is more serious than non-smokers. The alveolar bone defects of smokers with chronic periodontitis present teeth and site-specific effects and the most serious area is located in maxillary molars palatal. The application of CBCT is conducive for the clinicians to have a better understanding of the alveolar bone defect forms??and provides more help to the diagnosis and treatment of periodontal disease.     

吸烟对慢性牙周炎患者牙槽骨缺损影响研究

目的 探讨吸烟对慢性牙周炎患者牙槽骨缺损的影响。方法 从2012年10月至2014年3月中国医科大学附属口腔医院牙周科确诊为慢性牙周炎的患者中选择吸烟与非吸烟患者各30例,分别作为吸烟组与非吸烟组。采用Florida探针检查其全口牙齿近中、远中、唇（颊）侧及舌（腭）侧4个位点的牙周探诊深度（PD）及附着丧失水平（AL）。采用锥形束CT（CBCT）对入选对象进行扫描,并应用其自带的NNT软件测量切牙区、尖牙区、前磨牙区及磨牙区牙齿近中、远中、唇（颊）侧及舌（腭）侧4个位点的牙槽骨缺损程度。结果 吸烟组与非吸烟组的PD和AL差异无统计学意义（P > 0.05）,吸烟组的平均牙槽骨缺损程度较非吸烟组重,差异有统计学意义（P < 0.05）。吸烟组与非吸烟组相比,相同牙位的各个位点牙槽骨缺损都较重,差异有统计学意义（P < 0.05）。两组中各牙位牙槽骨缺损程度最轻的部位位于尖牙区,缺损程度最重的部位位于磨牙区（P < 0.05）。吸烟组中相同牙位的不同位点之间牙槽骨缺损程度差异有统计学意义（P < 0.05）,其中缺损程度最重的位于上颌磨牙区腭侧;除下颌磨牙区远中位点和下颌切牙区颊舌侧位点外,上颌各牙位牙槽骨缺损程度较下颌相应牙位重,差异有统计学意义（P < 0.05）。非吸烟组中不同牙位相同位点的牙槽骨缺损程度自磨牙区向尖牙区呈逐渐减小的趋势;但下颌切牙区各位点牙槽骨缺损程度明显高于上颌切牙区,差异有统计学意义（P < 0.05）。结论 慢性牙周炎患者中,吸烟者较非吸烟者牙槽骨缺损重。吸烟对于慢性牙周炎患者牙槽骨缺损的影响存在牙位和位点特异性表现,最严重的部位位于上颌磨牙区腭侧。CBCT的应用有利于临床医生更好地了解牙槽骨缺损的形式,会对牙周病诊断及治疗提供更大的帮助。