Into how many segments the infant's gum pad is divided?

 # Into how many segments the infant's gum pad is divided?

A. Two in each quadrant

B. Three in each quadrant

C. Two in each jaw

D. Five in each quadrant

The correct answer is D. Five in each quadrant.

At birth, the alveolar processes, are called gum pads. Dental groove divides gum pad into labial and lingual parts. Transverse groove further divides gum pad into ten segments in each jaw. Each of the

segment houses a developing tooth sac. The transverse groove between canine and first molar called lateral sulcus, is helpful in predicting inter-arch relationship. The maxillary arch is wider and longer than its counterpart. The gum pads contact the mandible arch around the molar region and space between the upper and lower gum pads in anterior region. This space between upper and lower gum

pads is called an infantile open bite.

Growth of the maxilla takes place by all of the following processes except:

 # Growth of the maxilla takes place by all of the following processes except:

A. Frontal process

B. Zygomatic process

C. Palatal process

D. Alveolar process

The correct answer is D. Alveolar process.

Scientific Rationale

The growth of the nasomaxillary complex is primarily driven by bone deposition at the circummaxillary suture system and widespread surface remodeling (apposition and resorption). The maxilla bone consists of a central body and four distinct processes. Three of these processes possess active sutural articulations that physically drive the skeletal displacement and overall expansion of the basal maxilla, while the fourth is functionally distinct.

1. Frontal Process (Sutural Growth Contributor)

The frontal process articulates with the frontal bone at the frontomaxillary suture. Bone deposition at this circummaxillary sutural site pushes the entire maxilla in a downward and forward direction relative to the anterior cranial base. This is a primary driver of midfacial skeletal expansion. 

2. Zygomatic Process (Sutural Growth Contributor)

The zygomatic process articulates with the zygomatic bone via the zygomaticomaxillary suture. Along with the frontomaxillary and pterygopalatine sutures, this is a major growth center. Bone deposition here responds to the downward and forward translatory displacement of the nasomaxillary complex.

3. Palatal Process (Sutural Growth Contributor)

The paired palatal processes articulate with each other at the midpalatal suture and with the horizontal plates of the palatine bones at the transverse palatine suture. Active growth at the midpalatal suture is the defining mechanism for the transverse skeletal expansion (width) of the maxilla.

4. Alveolar Process (The Exception)

Unlike the other three anatomical processes, the alveolar process lacks any sutural articulations that thrust or displace the maxilla against the cranium or facial bones.

• Tooth-Dependent Structure: As defined by Moss's Functional Matrix Theory, the alveolar process functions as a "microskeletal unit." Its development and growth are entirely dependent upon its functional matrix, which consists of the developing and erupting teeth.

• Appositional Surface Remodeling: It does not grow via sutural displacement. It forms strictly via vertical surface apposition (adding height and depth) in direct response to odontogenesis.

• Clinical Evidence: In clinical cases of congenital anodontia (complete absence of teeth), the alveolar process completely fails to develop. Despite this absence, the basal maxilla still achieves its normal anteroposterior and transverse dimensions because its true skeletal growth—driven by the frontal, zygomatic, and palatal processes—continues independently.

Therefore, while the alveolar process certainly undergoes localized growth, it is a dependent adaptive structure rather than a primary mechanism by which the basal maxilla physically grows and displaces.

# Who was the first certified specialist in orthodontics in the United States?

  # Who was the first certified specialist in orthodontics in the United States?

A. Edward H. Angle

B. Charles H. Tweed

C. Peter C. Kesling

D. John Nutting Farrar

The correct answer is B. Charles H. Tweed.

When Charles H. Tweed graduated from an improvised Angle course given by George Hahn in 1928, he was 33 years old, and Angle was 73. Angle was bitterly disappointed by the reception that had been accorded the edgewise appliance. He was infuriated and bitter about the modifications that were being made by several of his graduates (e.g., Spencer Adkinson). To him, it was obvious that something

had to be done if the edgewise appliance was to endure. 

Angle decided that an article describing the appliance must be published in Dental Cosmos. He asked Tweed to help him with the article because Tweed had just finished the Angle “course” and because he

admired and respected Tweed’s ability. For 7 weeks, they work together and in the process became close friends. During this time, Angle advised Tweed that he could never master the edgewise appliance unless he limited his practice solely to its use. Following the completion of the article for Dental Cosmos, Charles Tweed returned to Arizona and established in Phoenix what was probably the first pure edgewise specialty practice in the United States. 

For the next 2 years, the two men worked together closely. Tweed treatment planned and treated his patients, and Angle acted as his advisor. Angle was pleased with Tweed’s treatment and was instrumental in getting Tweed on several programs. During these 2 years, in a series of more than 100

letters that are now housed in the Tweed Memorial Center Library, Angle urged his young disciple to carry out two vital requests: (1) to dedicate his life to the development of the edgewise appliance and (2) to make every effort to establish orthodontics as a specialty within the dental profession.

Tweed followed Angle’s advice. First, he instigated the passing of the first orthodontic specialty law in the United States. He did this by canvassing patients, persuading dentists, influencing and arousing politicians, speaking at meetings, having petitions signed, and even taking patients before the legislature. In short, it was a one-man blitz. His untiring and relentless efforts were successful, and in 1929, the Arizona legislature passed the first law limiting the practice of orthodontics to specialists. Tweed received Certificate No. 1 in Arizona and became the first certified specialist in orthodontics in the United States.



Statistically significant vs Clinically Significant

Does statistically significant always mean clinically significant? What are the sensitivity and specificity of statistical significance when being used for clinical significance? Is it true that when something has been found to be statistically significant, it must be clinically significant too?

1. Does statistically significant always mean clinically significant?

No, statistical significance absolutely does not always equate to clinical significance.

• Statistical Significance merely indicates that the observed difference or effect in the study sample is unlikely to be due to chance, assuming the null hypothesis is true (typically indicated by a  p-value < 0.05) (Norman & Streiner, 2014). It is mathematically driven and heavily dependent on the sample size.

• Clinical Significance refers to the practical importance of a finding. It indicates whether an intervention makes a genuine, palpable difference in patient care, treatment efficiency, or functional/esthetic outcomes—often referred to as the Minimal Clinically Important Difference (MCID) (Pandis et al., 2010).

• Orthodontic Example: A study might find that a new aligner material corrects crowding 0.15 millimeters faster than a traditional material. If the study evaluates 5,000 patients, this 0.15 mm difference will likely be highly statistically significant (p < 0.001). However, 0.15 mm is imperceptible to both the orthodontist and the patient, rendering it completely clinically insignificant (Proffit et al., 2018).

Not all statistical differences are clinically significant, and sometimes differences that do not reach statistical significance nevertheless may indicate a clinical advance.

2. What are the sensitivity and specificity of statistical significance when being used for clinical significance?

If we evaluate "Statistical Significance" (SS) as if it were a diagnostic test for detecting true "Clinical Significance" (CS), the diagnostic performance metrics are skewed:

• Sensitivity (True Positive Rate) is High: If an orthodontic treatment truly has a massive, clinically significant effect (e.g., functional appliances reducing overjet by 6 mm), the statistical test will easily detect it. Thus, SS is highly sensitive to true clinical relevance, provided the study is adequately powered (Altman, 1991).

• Specificity (True Negative Rate) is Low: Specificity asks: If an effect is NOT clinically significant, will the statistical test correctly flag it as non-significant? In modern research with large sample sizes, the test fails at this. Large studies will frequently detect tiny, meaningless differences and label them as statistically significant. Therefore, relying purely on p-values produces many "false positives" for clinical relevance (Button et al., 2013).

3. Is it true that when something has been found to be statistically significant, it must be clinically significant too?

No, this is one of the most common epidemiological fallacies in dental research. As explained above, statistical significance only proves that a difference exists, not that the difference matters. To establish clinical significance, an orthodontist must look past the p-value and examine the effect size (magnitude of the change) and the confidence intervals to determine if the treatment alters clinical protocols in the real world (Johnston, 2002).

---

References:

• Altman DG (1991). Practical Statistics for Medical Research. Chapman and Hall/CRC.

• Button KS, et al. (2013). Power failure: why small sample size undermines the reliability of neuroscience. Nature Reviews Neuroscience.

• Johnston LE (2002). Clinical studies in orthodontics: art, science, or nonsense? American Journal of Orthodontics and Dentofacial Orthopedics.

• Norman GR, Streiner DL (2014). Biostatistics: The Bare Essentials. PMPH-USA.

• Pandis N, Polychronopoulou A, Eliades T (2010). Failure to establish a clinically significant difference... American Journal of Orthodontics and Dentofacial Orthopedics.

• Proffit WR, Fields HW, Larson BE, Sarver DM (2018). Contemporary Orthodontics, 6th Edition. Elsevier.